ucfopen__canvasapi-716

The problem describes a bug in `obj_or_str` utility function.
`obj_or_str` is supposed to work similarly to `obj_or_id`.
`obj_or_id` allows providing either an ID (as an `int`) or an object, and it returns the ID.
`obj_or_str` should allow providing either a string identifier or an object, and it should return the string identifier.

The problem states that `obj_or_str` improperly rejects strings.

I need to:
1. Find where `obj_or_id` and `obj_or_str` are defined.
2. Understand how `obj_or_id` is implemented.
3. Fix `obj_or_str` to align with `obj_or_id`'s logic.
4. Verify the fix.

Step 1: Locate `obj_or_id` and `obj_or_str`. They are likely in `canvasapi/util.py` or some other utility file.

{
  "command": "grep -rn --include=\"*.py\" -e \"def obj_or_id\" -e \"def obj_or_str\" canvasapi/"
}

{
  "status": "ok",
  "stdout": "canvasapi/util.py:101:def obj_or_id(parameter, param_name, object_types):\ncanvasapi/util.py:136:def obj_or_str(obj, attr, object_types):\n",
  "stderr": "",
  "exit_code": 0
}

Okay, both are in `canvasapi/util.py`.

Let's examine the implementations of `obj_or_id` and `obj_or_str`.

{
  "end_line": 150,
  "filepath": "canvasapi/util.py",
  "start_line": 100
}

{
  "status": "ok",
  "filepath": "canvasapi/util.py",
  "content": "\ndef obj_or_id(parameter, param_name, object_types):\n    \"\"\"\n    Accepts either an int (or long or str representation of an integer)\n    or an object. If it is an int, return it. If it is an object and\n    the object is of correct type, return the object's id. Otherwise,\n    throw an exception.\n\n    :param parameter: int, str, long, or object\n    :param param_name: str\n    :param object_types: tuple\n    :rtype: int\n    \"\"\"\n    from canvasapi.user import User\n\n    try:\n        return int(parameter)\n    except (ValueError, TypeError):\n        # Special case where 'self' is a valid ID of a User object\n        if User in object_types and parameter == \"self\":\n            return parameter\n\n        for obj_type in object_types:\n            if isinstance(parameter, obj_type):\n                try:\n                    return int(parameter.id)\n                except Exception:\n                    break\n\n        obj_type_list = \",\".join([obj_type.__name__ for obj_type in object_types])\n        message = \"Parameter {} must be of type {} or int.\".format(\n            param_name, obj_type_list\n        )\n        raise TypeError(message)\n\n\ndef obj_or_str(obj, attr, object_types):\n    \"\"\"\n    Accepts an object. If the object has the attribute, return the\n    corresponding string. Otherwise, throw an exception.\n\n    :param obj: object from which to retrieve attribute\n    :type obj: object\n    :param attr: name of the attribute to retrieve\n    :type attr: str\n    :param object_types: tuple containing the types of the object being passed in\n    :type object_types: tuple\n    :rtype: str\n    \"\"\"\n    try:\n        return str(getattr(obj, attr))",
  "start_line": 100,
  "end_line": 150,
  "total_lines": 244,
  "is_truncated": false
}

Wait, `read_file` truncated `obj_or_str` because I only read up to line 150 and `obj_or_str` starts at 136. Let me read more.

{
  "end_line": 170,
  "filepath": "canvasapi/util.py",
  "start_line": 130
}

{
  "status": "ok",
  "filepath": "canvasapi/util.py",
  "content": "        message = \"Parameter {} must be of type {} or int.\".format(\n            param_name, obj_type_list\n        )\n        raise TypeError(message)\n\n\ndef obj_or_str(obj, attr, object_types):\n    \"\"\"\n    Accepts an object. If the object has the attribute, return the\n    corresponding string. Otherwise, throw an exception.\n\n    :param obj: object from which to retrieve attribute\n    :type obj: object\n    :param attr: name of the attribute to retrieve\n    :type attr: str\n    :param object_types: tuple containing the types of the object being passed in\n    :type object_types: tuple\n    :rtype: str\n    \"\"\"\n    try:\n        return str(getattr(obj, attr))\n    except (AttributeError, TypeError):\n        if not isinstance(attr, str):\n            raise TypeError(\n                \"Atttibute parameter {} must be of type string\".format(attr)\n            )\n        for obj_type in object_types:\n            if isinstance(obj, obj_type):\n                try:\n                    return str(getattr(obj, attr))\n                except AttributeError:\n                    raise AttributeError(\"{} object does not have {} attribute\").format(\n                        obj, attr\n                    )\n\n        obj_type_list = \",\".join([obj_type.__name__ for obj_type in object_types])\n        raise TypeError(\"Parameter {} must be of type {}.\".format(obj, obj_type_list))\n\n\ndef get_institution_url(base_url):\n    \"\"\"",
  "start_line": 130,
  "end_line": 170,
  "total_lines": 244,
  "is_truncated": false
}

Wait, `obj_or_str` implementation is:

```python
def obj_or_str(obj, attr, object_types):
    """
    Accepts an object. If the object has the attribute, return the
    corresponding string. Otherwise, throw an exception.

    :param obj: object from which to retrieve attribute
    :type obj: object
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
    try:
        return str(getattr(obj, attr))
    except (AttributeError, TypeError):
        if not isinstance(attr, str):
            raise TypeError(
                "Atttibute parameter {} must be of type string".format(attr)
            )
        for obj_type in object_types:
            if isinstance(obj, obj_type):
                try:
                    return str(getattr(obj, attr))
                except AttributeError:
                    raise AttributeError("{} object does not have {} attribute").format(
                        obj, attr
                    )

        obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
        raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))
```

The problem is that `obj_or_str` does NOT check if `obj` is already a string.
If `obj` is a string, `getattr(obj, attr)` will likely fail unless the string has an attribute named `attr`.

If `obj` is a string, `obj_or_str` should just return the string.

Compare with `obj_or_id`:
```python
def obj_or_id(parameter, param_name, object_types):
    # ... docstring ...
    try:
        return int(parameter)
    except (ValueError, TypeError):
        # ... check User 'self' ...
        for obj_type in object_types:
            if isinstance(parameter, obj_type):
                try:
                    return int(parameter.id)
                except Exception:
                    break
        # ... raise TypeError ...
```

`obj_or_id` first tries `int(parameter)`. If that fails, it checks if `parameter` is one of the allowed object types and gets its `.id`.

`obj_or_str` should probably try to see if `obj` is already a string (or can be converted to one in a way that makes sense as a "string identifier"), and if not, check if it's one of the allowed object types and get the attribute `attr`.

Wait, if `obj` is a string, `getattr(obj, attr)` will almost certainly raise `AttributeError`.
The `except (AttributeError, TypeError):` block is entered.
Then it checks if `attr` is a string.
Then it checks if `obj` is one of `object_types`. If `obj` is a string and `str` is not in `object_types`, it will raise a `TypeError`.

So if I call `obj_or_str("my_feature_flag", "name", (FeatureFlag,))`, it will:
1. `getattr("my_feature_flag", "name")` -> `AttributeError` (strings don't have `name` attribute).
2. `isinstance("my_feature_flag", (FeatureFlag,))` -> `False`.
3. `TypeError("Parameter my_feature_flag must be of type FeatureFlag.")`.

But it should have just returned `"my_feature_flag"`.

Correct logic for `obj_or_str` (patterned after `obj_or_id`):
1. If `obj` is a string, return it.
2. If `obj` is one of the `object_types`, return `str(getattr(obj, attr))`.
3. Otherwise, raise `TypeError`.

Actually, `obj_or_id` does `int(parameter)` first.
For `obj_or_str`, should we do `str(obj)` first? No, because almost everything can be converted to a string. We specifically want to know if it's *already* a string identifier, or if it's an object from which we can *extract* a string identifier.

So the implementation should be:
```python
def obj_or_str(obj, attr, object_types):
    if isinstance(obj, str):
        return obj
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                # This part is tricky. If it's the right type but missing the attribute,
                # should we raise AttributeError or keep looking?
                # The current implementation raises AttributeError.
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))
    
    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

Wait, let's look at the existing `obj_or_str` again.
```python
    try:
        return str(getattr(obj, attr))
    except (AttributeError, TypeError):
        if not isinstance(attr, str):
            raise TypeError(
                "Atttibute parameter {} must be of type string".format(attr)
            )
        for obj_type in object_types:
            if isinstance(obj, obj_type):
                try:
                    return str(getattr(obj, attr))
                except AttributeError:
                    raise AttributeError("{} object does not have {} attribute").format(
                        obj, attr
                    )

        obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
        raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))
```

Wait, there is a bug in the existing `obj_or_str`'s `AttributeError` raise:
`raise AttributeError("{} object does not have {} attribute").format(obj, attr)`
The `.format()` is called on the exception *class* (or the result of the constructor) but the closing parenthesis for `AttributeError()` is BEFORE `.format()`.
Actually:
`raise AttributeError("{} object does not have {} attribute").format(obj, attr)`
`AttributeError("{} object does not have {} attribute")` creates an exception object.
Then `.format(obj, attr)` is called on that exception object. `BaseException` does NOT have a `.format()` method. This will raise an `AttributeError: 'AttributeError' object has no attribute 'format'`.

Also, there is a typo in `"Atttibute parameter {} must be of type string"`. "Atttibute" has 3 't's.

Let's double check `obj_or_id` again.
```python
def obj_or_id(parameter, param_name, object_types):
    # ...
    try:
        return int(parameter)
    except (ValueError, TypeError):
        # Special case where 'self' is a valid ID of a User object
        if User in object_types and parameter == "self":
            return parameter

        for obj_type in object_types:
            if isinstance(parameter, obj_type):
                try:
                    return int(parameter.id)
                except Exception:
                    break
    # ...
```

If I want `obj_or_str` to be "more in line with `obj_or_id`", it should:
1. Check if it's already a string.
2. If not, check if it's one of the object types and extract the attribute.

Let's create a reproduction script.

{
  "command": "python3 - <<'PY'\nfrom canvasapi.util import obj_or_str\n\nclass MockFeature:\n    def __init__(self, name):\n        self.name = name\n\nobject_types = (MockFeature,)\n\n# Test 1: Pass a string. Should return the string.\ntry:\n    res = obj_or_str(\"feature_1\", \"name\", object_types)\n    print(f\"Test 1 (string): Success, got {res}\")\nexcept Exception as e:\n    print(f\"Test 1 (string): Failed, got {type(e).__name__}: {e}\")\n\n# Test 2: Pass an object. Should return the attribute.\ntry:\n    feat = MockFeature(\"feature_2\")\n    res = obj_or_str(feat, \"name\", object_types)\n    print(f\"Test 2 (object): Success, got {res}\")\nexcept Exception as e:\n    print(f\"Test 2 (object): Failed, got {type(e).__name__}: {e}\")\n\n# Test 3: Pass an invalid object. Should raise TypeError.\ntry:\n    res = obj_or_str(123, \"name\", object_types)\n    print(f\"Test 3 (invalid): Failed, got {res}\")\nexcept TypeError as e:\n    print(f\"Test 3 (invalid): Success, got TypeError: {e}\")\nexcept Exception as e:\n    print(f\"Test 3 (invalid): Failed, got {type(e).__name__}: {e}\")\nPY\n"
}

{
  "status": "ok",
  "stdout": "Test 1 (string): Failed, got TypeError: Parameter feature_1 must be of type MockFeature.\nTest 2 (object): Success, got feature_2\nTest 3 (invalid): Success, got TypeError: Parameter 123 must be of type MockFeature.\n",
  "stderr": "",
  "exit_code": 0
}

Confirmed. `Test 1 (string)` failed with `TypeError: Parameter feature_1 must be of type MockFeature.`

Now let's fix `obj_or_str`.

I'll implement it to:
1. Check if `obj` is a string.
2. If not, check if it's one of the `object_types`.
3. If it's one of the `object_types`, get the attribute `attr` and convert to string.
4. Otherwise, raise `TypeError`.

Wait, should I keep the `try: return str(getattr(obj, attr))` at the beginning?
In `obj_or_id`, it does `try: return int(parameter)`.
If `parameter` is already an int, `int(parameter)` returns it. If it's a string that looks like an int, `int(parameter)` converts it.

For `obj_or_str`, if `obj` is already a string, `str(obj)` returns it.
However, `getattr(obj, attr)` will fail if `obj` is a string and not the specific object type we are looking for.

So if I do:
```python
def obj_or_str(obj, attr, object_types):
    if isinstance(obj, str):
        return obj
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))
    
    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

Wait, does `obj_or_id` have this `User` special case?
```python
        # Special case where 'self' is a valid ID of a User object
        if User in object_types and parameter == "self":
            return parameter
```
Does `obj_or_str` need something similar? The problem description doesn't mention it.

Let's look at how `obj_or_id` is structured.
```python
def obj_or_id(parameter, param_name, object_types):
    from canvasapi.user import User

    try:
        return int(parameter)
    except (ValueError, TypeError):
        # Special case where 'self' is a valid ID of a User object
        if User in object_types and parameter == "self":
            return parameter

        for obj_type in object_types:
            if isinstance(parameter, obj_type):
                try:
                    return int(parameter.id)
                except Exception:
                    break

        obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
        message = "Parameter {} must be of type {} or int.".format(
            param_name, obj_type_list
        )
        raise TypeError(message)
```

Let's try to mirror this for `obj_or_str`.
`parameter` -> `obj`
`param_name` -> `attr` (wait, `attr` in `obj_or_str` is the attribute name, e.g., "name", not the parameter name like "course_id")

Looking at `obj_or_str` signature: `def obj_or_str(obj, attr, object_types):`
It doesn't take a `param_name`.

The usage of `obj_or_str` in other functions:
- `canvasapi.account.Account.get_feature_flag()`
- `canvasapi.course.Course.get_feature_flag()`
- `canvasapi.feature.FeatureFlag.delete()`
- `canvasapi.feature.FeatureFlag.set_feature_flag()`
- `canvasapi.user.User.get_feature_flag()`

Let's see one of these callers.

{
  "command": "grep -rn \"obj_or_str\" canvasapi/"
}

{
  "status": "ok",
  "stdout": "canvasapi/user.py:17:from canvasapi.util import combine_kwargs, obj_or_id, obj_or_str\ncanvasapi/user.py:515:        feature_name = obj_or_str(feature, \"name\", (Feature,))\ncanvasapi/account.py:24:from canvasapi.util import combine_kwargs, file_or_path, obj_or_id, obj_or_str\ncanvasapi/account.py:1103:        feature_name = obj_or_str(feature, \"name\", (Feature,))\ncanvasapi/util.py:136:def obj_or_str(obj, attr, object_types):\ncanvasapi/course.py:47:    obj_or_str,\ncanvasapi/course.py:1327:        feature_name = obj_or_str(feature, \"name\", (Feature,))\ncanvasapi/feature.py:2:from canvasapi.util import combine_kwargs, obj_or_str\ncanvasapi/feature.py:71:        feature_name = obj_or_str(feature, \"name\", (Feature,))\ncanvasapi/feature.py:103:        feature_name = obj_or_str(feature, \"name\", (Feature,))\n",
  "stderr": "",
  "exit_code": 0
}

In all cases, it's called like `obj_or_str(feature, "name", (Feature,))`.
So `obj` is the feature, `attr` is `"name"`, and `object_types` is `(Feature,)`.

If the user passes a string as `feature`, `obj_or_str` should return that string.

So the proposed implementation:
```python
def obj_or_str(obj, attr, object_types):
    if isinstance(obj, str):
        return obj
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                # Mirrors the intent of the original code, but fixes the .format bug
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))
    
    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

Wait, the original `obj_or_str` had this `try...except` at the beginning:
```python
    try:
        return str(getattr(obj, attr))
    except (AttributeError, TypeError):
        # ...
```

If `obj` is a string, `getattr(obj, "name")` will raise `AttributeError`.
The current implementation then enters the `except` block.

If I change it to:
```python
def obj_or_str(obj, attr, object_types):
    if isinstance(obj, str):
        return obj
    # ...
```
It solves the problem.

Is there any case where `getattr(obj, attr)` should be tried *before* checking `object_types`?
Probably not, because if it's not a string and it's not one of the requested `object_types`, we want to raise a `TypeError`.

Actually, `obj_or_id` does:
```python
    try:
        return int(parameter)
    except (ValueError, TypeError):
```
This is like saying "if it's already an int (or convertible to int), return it".

For `obj_or_str`, if we want it to be "more in line with `obj_or_id`", we should probably check if it's a string first.

Let's look at the current implementation of `obj_or_str` again to see if it's doing anything else.
```python
    try:
        return str(getattr(obj, attr))
    except (AttributeError, TypeError):
        if not isinstance(attr, str):
            raise TypeError(
                "Atttibute parameter {} must be of type string".format(attr)
            )
        for obj_type in object_types:
            if isinstance(obj, obj_type):
                try:
                    return str(getattr(obj, attr))
                except AttributeError:
                    # BUG HERE
                    raise AttributeError("{} object does not have {} attribute").format(
                        obj, attr
                    )

        obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
        # BUG HERE (missing closing quote)
        raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))
```

Wait, I just noticed another bug in the original code:
`raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))`
The `\"` at the end of the string is actually escaping the quote.
So the string is `"Parameter {} must be of type {}. \"`.
And then `.format(obj, obj_type_list)` is called on the string.
This part actually works (unlike the `AttributeError` call), but it's ugly.

Let's verify the `TypeError` and `AttributeError` bugs in the original code first.

{
  "command": "python3 - <<'PY'\nfrom canvasapi.util import obj_or_str\n\nclass MockFeature:\n    def __init__(self, name):\n        self.name = name\n\nobject_types = (MockFeature,)\n\n# Test 1: Pass a string. Should return the string. (Currently fails with TypeError)\ntry:\n    res = obj_or_str(\"feature_1\", \"name\", object_types)\n    print(f\"Test 1: Success, got {res}\")\nexcept Exception as e:\n    print(f\"Test 1: Failed, got {type(e).__name__}: {e}\")\n\n# Test 2: Pass an object of right type. Should work.\ntry:\n    feat = MockFeature(\"feature_2\")\n    res = obj_or_str(feat, \"name\", object_types)\n    print(f\"Test 2: Success, got {res}\")\nexcept Exception as e:\n    print(f\"Test 2: Failed, got {type(e).__name__}: {e}\")\n\n# Test 3: Pass an object of right type but missing attribute. Should raise AttributeError (or a BUGGY RuntimeError)\nclass BrokenFeature:\n    pass\n\ntry:\n    feat = BrokenFeature()\n    # We must pass (BrokenFeature,) as object_types for it to enter the loop\n    res = obj_or_str(feat, \"name\", (BrokenFeature,))\n    print(f\"Test 3: Failed, got {res}\")\nexcept AttributeError as e:\n    print(f\"Test 3: Success, got AttributeError: {e}\")\nexcept Exception as e:\n    print(f\"Test 3: Failed, got {type(e).__name__}: {e}\")\n\n# Test 4: Pass an invalid object. Should raise TypeError.\ntry:\n    res = obj_or_str(123, \"name\", object_types)\n    print(f\"Test 4: Failed, got {res}\")\nexcept TypeError as e:\n    print(f\"Test 4: Success, got TypeError: {e}\")\nexcept Exception as e:\n    print(f\"Test 4: Failed, got {type(e).__name__}: {e}\")\nPY\n"
}

{
  "status": "ok",
  "stdout": "Test 1: Failed, got TypeError: Parameter feature_1 must be of type MockFeature.\nTest 2: Success, got feature_2\nTest 3: Success, got AttributeError: 'AttributeError' object has no attribute 'format'\nTest 4: Success, got TypeError: Parameter 123 must be of type MockFeature.\n",
  "stderr": "",
  "exit_code": 0
}

Test 3 confirms the `AttributeError`Bug: `got AttributeError: 'AttributeError' object has no attribute 'format'`.
Wait, the exception raised was `AttributeError`, but the message was `'AttributeError' object has no attribute 'format'`.
This is because `AttributeError("...").format()` failed and raised a NEW `AttributeError`.

So the synthesis of the fix:
1. Handle strings immediately.
2. Handle the object types and extract the attribute.
3. Fix the `AttributeError` formatting bug.
4. Fix the `TypeError` formatting bug (and the "Atttibute" typo if I can, although the task is specifically about `obj_or_str` improperly rejecting strings).

Let's refine the implementation for `obj_or_str`:

```python
def obj_or_str(obj, attr, object_types):
    """
    Accepts an object or a string. If it is a string, return it.
    If it is an object and the object is of correct type, return the
    object's attribute as a string. Otherwise, throw an exception.

    :param obj: object or string from which to retrieve attribute
    :type obj: object or str
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
    if isinstance(obj, str):
        return obj
    
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))

    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

Wait, I should check if `attr` is actually a string.
The original code had:
```python
        if not isinstance(attr, str):
            raise TypeError(
                "Atttibute parameter {} must be of type string".format(attr)
            )
```
If `attr` is not a string, `getattr(obj, attr)` will raise `TypeError`.
In my proposed implementation, if `obj` is not a string, it enters the loop. If `attr` is not a string, `getattr(obj, attr)` will raise `TypeError`. This `TypeError` is not caught, so it propagates.

Is that acceptable?
In `obj_or_id`, `param_name` is used in the final `TypeError` message.
In `obj_or_str`, `attr` is the attribute name.

If `attr` is passed as something other than a string, it's a programmer error in the library, not a user error. The library functions call `obj_or_str(feature, "name", (Feature,))`.

Let's check if I should keep the `attr` type check.
The problem statement says "Update `obj_or_str` to be more in line with `obj_or_id`".
`obj_or_id` doesn't check the type of `param_name`.

Actually, looking at the original `obj_or_str`, the `attr` type check was inside the `except` block.
So if `getattr(obj, attr)` succeeded, the type check for `attr` was never performed. (Which is weird, because if `getattr` succeeded, `attr` MUST have been a valid attribute name, usually a string).

So I think it's safe to remove that check or just let `getattr` raise its own `TypeError`.

Let's compare `obj_or_id`'s structure again.
```python
def obj_or_id(parameter, param_name, object_types):
    # ...
    try:
        return int(parameter)
    except (ValueError, TypeError):
        # ... User 'self' check ...
        for obj_type in object_types:
            if isinstance(parameter, obj_type):
                try:
                    return int(parameter.id)
                except Exception:
                    break
        # ... TypeError ...
```

My proposed `obj_or_str`:
```python
def obj_or_str(obj, attr, object_types):
    if isinstance(obj, str):
        return obj
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))
    
    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

This feels correct and much cleaner.

Wait, one more thing. `obj_or_id` uses `int(parameter.id)`.
`obj_or_str` uses `str(getattr(obj, attr))`.
This is consistent.

Let's double check the docstring.
The original docstring:
```python
    """
    Accepts an object. If the object has the attribute, return the
    corresponding string. Otherwise, throw an exception.

    :param obj: object from which to retrieve attribute
    :type obj: object
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
```
I should update the docstring to reflect that it now accepts strings too.

Actually, `obj_or_id`'s docstring says:
```python
    """
    Accepts either an int (or long or str representation of an integer)
    or an object. If it is an int, return it. If it is an object and
    the object is of correct type, return the object's id. Otherwise,
    throw an exception.
```

So for `obj_or_str`:
```python
    """
    Accepts either a string or an object. If it is a string, return it. 
    If it is an object and the object is of correct type, return the 
    object's attribute as a string. Otherwise, throw an exception.

    :param obj: string or object from which to retrieve attribute
    :type obj: str or object
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
```

Wait, I should be careful about the exact format of the docstring in the original file if I want to minimize diff noise, but fixing the bug and updating the docstring is good.

Let's look at the lines in `canvasapi/util.py` to prepare `edit_file`.
Lines 136-168.

```python
def obj_or_str(obj, attr, object_types):
    """
    Accepts an object. If the object has the attribute, return the
    corresponding string. Otherwise, throw an exception.

    :param obj: object from which to retrieve attribute
    :type obj: object
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
    try:
        return str(getattr(obj, attr))
    except (AttributeError, TypeError):
        if not isinstance(attr, str):
            raise TypeError(
                "Atttibute parameter {} must be of type string".format(attr)
            )
        for obj_type in object_types:
            if isinstance(obj, obj_type):
                try:
                    return str(getattr(obj, attr))
                except AttributeError:
                    raise AttributeError("{} object does not have {} attribute").format(
                        obj, attr
                    )

        obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
        raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))
```

Wait, the last line `raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))` in the original code I read earlier was:
`raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))`
Let me re-read the file carefully around there.

{
  "end_line": 168,
  "filepath": "canvasapi/util.py",
  "start_line": 136
}

{
  "status": "ok",
  "filepath": "canvasapi/util.py",
  "content": "def obj_or_str(obj, attr, object_types):\n    \"\"\"\n    Accepts an object. If the object has the attribute, return the\n    corresponding string. Otherwise, throw an exception.\n\n    :param obj: object from which to retrieve attribute\n    :type obj: object\n    :param attr: name of the attribute to retrieve\n    :type attr: str\n    :param object_types: tuple containing the types of the object being passed in\n    :type object_types: tuple\n    :rtype: str\n    \"\"\"\n    try:\n        return str(getattr(obj, attr))\n    except (AttributeError, TypeError):\n        if not isinstance(attr, str):\n            raise TypeError(\n                \"Atttibute parameter {} must be of type string\".format(attr)\n            )\n        for obj_type in object_types:\n            if isinstance(obj, obj_type):\n                try:\n                    return str(getattr(obj, attr))\n                except AttributeError:\n                    raise AttributeError(\"{} object does not have {} attribute\").format(\n                        obj, attr\n                    )\n\n        obj_type_list = \",\".join([obj_type.__name__ for obj_type in object_types])\n        raise TypeError(\"Parameter {} must be of type {}.\".format(obj, obj_type_list))\n\n",
  "start_line": 136,
  "end_line": 168,
  "total_lines": 244,
  "is_truncated": false
}

Ah, I see. The last line was:
`raise TypeError("Parameter {} must be of type {}.\".format(obj, obj_type_list))`
Wait, looking at the response:
`raise TypeError(\"Parameter {} must be of type {}.\".format(obj, obj_type_list))`
The `\"` is just because it's in a JSON string. The actual line in the file is:
`raise TypeError("Parameter {} must be of type {}".format(obj, obj_type_list))`
Wait, no. The JSON is `\"Parameter {} must be of type {}.\".format(obj, obj_type_list))`.
This means the string literal is `"Parameter {} must be of type {}.`.
And then `.format()` is called.
Actually, looking at the JSON:
`raise TypeError(\"Parameter {} must be of type {}.\".format(obj, obj_type_list))`
The `\"` is the start of the Python string.
The `.` after `{}` is inside the string.
The `\"` before `.format` is the END of the Python string.
Wait: `\"Parameter {} must be of type {}.\"`
So the string is `"Parameter {} must be of type {}."`.
Then `.format(obj, obj_type_list)` is called on that string.
Then the result is passed to `TypeError()`.
So that line was actually correct (except for missing "or str" in the message).

But the `AttributeError` line is definitely wrong:
`raise AttributeError(\"{} object does not have {} attribute\").format(obj, attr)`
Here, `AttributeError("...")` is called first, creating an exception object, and then `.format()` is called on that exception object.

Anyway, I will replace the entire function.

```python
def obj_or_str(obj, attr, object_types):
    """
    Accepts either a string or an object. If it is a string, return it.
    If it is an object and the object is of correct type, return the
    object's attribute as a string. Otherwise, throw an exception.

    :param obj: string or object from which to retrieve attribute
    :type obj: str or object
    :param attr: name of the attribute to retrieve
    :type attr: str
    :param object_types: tuple containing the types of the object being passed in
    :type object_types: tuple
    :rtype: str
    """
    if isinstance(obj, str):
        return obj
    for obj_type in object_types:
        if isinstance(obj, obj_type):
            try:
                return str(getattr(obj, attr))
            except AttributeError:
                raise AttributeError("{} object does not have {} attribute".format(obj, attr))

    obj_type_list = ",".join([obj_type.__name__ for obj_type in object_types])
    raise TypeError("Parameter {} must be of type {} or str.".format(obj, obj_type_list))
```

Let's make sure I have the exact `old_string` for `edit_file`.

{
  "command": "python3 - <<'PY'\nwith open('canvasapi/util.py', 'r') as f:\n    lines = f.readlines()\n    start = 0\n    for i, line in enumerate(lines):\n        if 'def obj_or_str(obj, attr, object_types):' in line:\n            start = i\n            break\n    \n    # Find the end of the function (where the next def or a blank line followed by a def is)\n    end = start\n    for i in range(start + 1, len(lines)):\n        if lines[i].startswith('def ') or (lines[i].strip() == '' and i + 1 < len(lines) and lines[i+1].startswith('def ')):\n            if lines[i].strip() != '':\n                end = i\n                break\n            else:\n                end = i + 1\n                break\n    \n    print(\"\".join(lines[start:end]))\nPY\n"
}

{
  "status": "ok",
  "stdout": "def obj_or_str(obj, attr, object_types):\n    \"\"\"\n    Accepts an object. If the object has the attribute, return the\n    corresponding string. Otherwise, throw an exception.\n\n    :param obj: object from which to retrieve attribute\n    :type obj: object\n    :param attr: name of the attribute to retrieve\n    :type attr: str\n    :param object_types: tuple containing the types of the object being passed in\n    :type object_types: tuple\n    :rtype: str\n    \"\"\"\n    try:\n        return str(getattr(obj, attr))\n    except (AttributeError, TypeError):\n        if not isinstance(attr, str):\n            raise TypeError(\n                \"Atttibute parameter {} must be of type string\".format(attr)\n            )\n        for obj_type in object_types:\n            if isinstance(obj, obj_type):\n                try:\n                    return str(getattr(obj, attr))\n                except AttributeError:\n                    raise AttributeError(\"{} object does not have {} attribute\").format(\n                        obj, attr\n                    )\n\n        obj_type_list = \",\".join([obj_type.__name__ for obj_type in object_types])\n        raise TypeError(\"Parameter {} must be of type {}.\".format(obj, obj_type_list))\n\n\n\n",
  "stderr": "",
  "exit_code": 0
}