We are currently solving the following issue within our repository. Here is the issue text:
--- BEGIN ISSUE ---
Write unit tests for `bot/rules/mentions.py`
Write unit tests for [`bot/rules/mentions.py`](../blob/master/bot/rules/mentions.py).

## Implementation details
Please make sure to read the general information in the [meta issue](553) and the [testing README](../blob/master/tests/README.md). We are aiming for a 100% [branch coverage](https://coverage.readthedocs.io/en/stable/branch.html) for this file, but if you think that is not possible, please discuss that in this issue.

## Additional information
If you want to work on this issue, **please make sure that you get assigned to it** by one of the core devs before starting to work on it. We would like to prevent the situation that multiple people are working on the same issue. To get assigned, leave a comment showing your interesting in tackling this issue.


--- END ISSUE ---

Below are some code segments, each from a relevant file. One or more of these files may contain bugs.
--- BEGIN FILES ---
Path: `bot/rules/attachments.py`
Content:
```
1 from typing import Dict, Iterable, List, Optional, Tuple
2 
3 from discord import Member, Message
4 
5 
6 async def apply(
7     last_message: Message, recent_messages: List[Message], config: Dict[str, int]
8 ) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
9     """Detects total attachments exceeding the limit sent by a single user."""
10     relevant_messages = [last_message] + [
11         msg
12         for msg in recent_messages
13         if (
14             msg.author == last_message.author
15             and len(msg.attachments) > 0
16         )
17     ]
18     total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)
19 
20     if total_recent_attachments > config['max']:
21         return (
22             f"sent {total_recent_attachments} attachments in {config['max']}s",
23             (last_message.author,),
24             relevant_messages
25         )
26     return None
27
```
--- END FILES ---

Please first localize the bug based on the issue statement, and then generate a patch according to the `git diff` format fenced by three backticks.

Here is an example:

```diff
diff --git a/examples/server_async.py b/examples/server_async.py
--- a/examples/server_async.py
+++ b/examples/server_async.py
@@ -313,4 +313,4 @@
 
 
 if __name__ == "__main__":
-    asyncio.run(run_async_server("."), debug=True)
+    asyncio.run(run_async_server(), debug=True)
diff --git a/examples/server_sync.py b/examples/server_sync.py
--- a/examples/server_sync.py
+++ b/examples/server_sync.py
@@ -313,5 +313,5 @@
 
 
 if __name__ == "__main__":
-    server = run_sync_server(".")
+    server = run_sync_server()
     server.shutdown()

```

diff --git a/bot/rules/attachments.py b/bot/rules/attachments.py
--- a/bot/rules/attachments.py
+++ b/bot/rules/attachments.py
@@ -7,14 +7,14 @@
     last_message: Message, recent_messages: List[Message], config: Dict[str, int]
 ) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:
     """Detects total attachments exceeding the limit sent by a single user."""
-    relevant_messages = [last_message] + [
+    relevant_messages = tuple(
         msg
         for msg in recent_messages
         if (
             msg.author == last_message.author
             and len(msg.attachments) > 0
         )
-    ]
+    )
     total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)
 
     if total_recent_attachments > config['max']:

{"golden_diff": "diff --git a/bot/rules/attachments.py b/bot/rules/attachments.py\n--- a/bot/rules/attachments.py\n+++ b/bot/rules/attachments.py\n@@ -7,14 +7,14 @@\n     last_message: Message, recent_messages: List[Message], config: Dict[str, int]\n ) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:\n     \"\"\"Detects total attachments exceeding the limit sent by a single user.\"\"\"\n-    relevant_messages = [last_message] + [\n+    relevant_messages = tuple(\n         msg\n         for msg in recent_messages\n         if (\n             msg.author == last_message.author\n             and len(msg.attachments) > 0\n         )\n-    ]\n+    )\n     total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)\n \n     if total_recent_attachments > config['max']:\n", "issue": "Write unit tests for `bot/rules/mentions.py`\nWrite unit tests for [`bot/rules/mentions.py`](../blob/master/bot/rules/mentions.py).\n\n## Implementation details\nPlease make sure to read the general information in the [meta issue](553) and the [testing README](../blob/master/tests/README.md). We are aiming for a 100% [branch coverage](https://coverage.readthedocs.io/en/stable/branch.html) for this file, but if you think that is not possible, please discuss that in this issue.\n\n## Additional information\nIf you want to work on this issue, **please make sure that you get assigned to it** by one of the core devs before starting to work on it. We would like to prevent the situation that multiple people are working on the same issue. To get assigned, leave a comment showing your interesting in tackling this issue.\n\n", "before_files": [{"content": "from typing import Dict, Iterable, List, Optional, Tuple\n\nfrom discord import Member, Message\n\n\nasync def apply(\n    last_message: Message, recent_messages: List[Message], config: Dict[str, int]\n) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:\n    \"\"\"Detects total attachments exceeding the limit sent by a single user.\"\"\"\n    relevant_messages = [last_message] + [\n        msg\n        for msg in recent_messages\n        if (\n            msg.author == last_message.author\n            and len(msg.attachments) > 0\n        )\n    ]\n    total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)\n\n    if total_recent_attachments > config['max']:\n        return (\n            f\"sent {total_recent_attachments} attachments in {config['max']}s\",\n            (last_message.author,),\n            relevant_messages\n        )\n    return None\n", "path": "bot/rules/attachments.py"}], "after_files": [{"content": "from typing import Dict, Iterable, List, Optional, Tuple\n\nfrom discord import Member, Message\n\n\nasync def apply(\n    last_message: Message, recent_messages: List[Message], config: Dict[str, int]\n) -> Optional[Tuple[str, Iterable[Member], Iterable[Message]]]:\n    \"\"\"Detects total attachments exceeding the limit sent by a single user.\"\"\"\n    relevant_messages = tuple(\n        msg\n        for msg in recent_messages\n        if (\n            msg.author == last_message.author\n            and len(msg.attachments) > 0\n        )\n    )\n    total_recent_attachments = sum(len(msg.attachments) for msg in relevant_messages)\n\n    if total_recent_attachments > config['max']:\n        return (\n            f\"sent {total_recent_attachments} attachments in {config['max']}s\",\n            (last_message.author,),\n            relevant_messages\n        )\n    return None\n", "path": "bot/rules/attachments.py"}]}