Add a function to get bound args

2 files changed, 17 insertions, 4 deletions

diff --git a/bot/decorators.py b/bot/decorators.py
index 7f58abd1c..ef4951141 100644
--- a/bot/decorators.py
+++ b/bot/decorators.py
@@ -12,6 +12,7 @@ from discord import Colour, Embed, Member, NotFound
 from discord.ext.commands import Cog, Command, Context, check
 
 from bot.constants import Channels, ERROR_REPLIES, RedirectOutput
+from bot.utils import function
 from bot.utils.checks import in_whitelist_check, with_role_check, without_role_check
 
 log = logging.getLogger(__name__)
@@ -123,12 +124,10 @@ def mutually_exclusive(namespace: t.Hashable, resource_id: ResourceId) -> t.Call
 
             if callable(resource_id):
                 log.trace(f"{name}: binding args to signature")
-                sig = inspect.signature(func)
-                bound_args = sig.bind(*args, **kwargs)
-                bound_args.apply_defaults()
+                bound_args = function.get_bound_args(func, args, kwargs)
 
                 log.trace(f"{name}: calling the given callable to get the resource ID")
-                id_ = resource_id(bound_args.arguments)
+                id_ = resource_id(bound_args)
 
                 if inspect.isawaitable(id_):
                     log.trace(f"{name}: awaiting to get resource ID")
diff --git a/bot/utils/function.py b/bot/utils/function.py
index 23188e79e..3ab32fe3c 100644
--- a/bot/utils/function.py
+++ b/bot/utils/function.py
@@ -1,5 +1,6 @@
 """Utilities for interaction with functions."""
 
+import inspect
 import typing as t
 
 Argument = t.Union[int, str]
@@ -59,3 +60,16 @@ def get_arg_value_wrapper(
         return value
 
     return decorator_func(wrapper)
+
+
+def get_bound_args(func: t.Callable, args: t.Tuple, kwargs: t.Dict[str, t.Any]) -> BoundArgs:
+    """
+    Bind `args` and `kwargs` to `func` and return a mapping of parameter names to argument values.
+
+    Default parameter values are also set.
+    """
+    sig = inspect.signature(func)
+    bound_args = sig.bind(*args, **kwargs)
+    bound_args.apply_defaults()
+
+    return bound_args.arguments