Removed docstring from Lib/asyncio/futures.py and added it in Doc/library/asyncio-future.rst

Author: Manoj

Doc/library/asyncio-future.rst

@@ -195,6 +195,10 @@ Future Object
       If the Future is already *done* or *cancelled*, return ``False``.
       Otherwise, change the Future's state to *cancelled*,
       schedule the callbacks, and return ``True``.
+      
+      The optional argument *msg* is passed as the argument to the
+      :exc:`CancelledError` exception raised when a cancelled Future
+      is awaited. It can be any object.
 
       .. versionchanged:: 3.9
          Added the *msg* parameter.

Lib/asyncio/futures.py

@@ -159,10 +159,6 @@ def cancel(self, msg=None):
         If the future is already done or cancelled, return False.  Otherwise,
         change the future's state to cancelled, schedule the callbacks and
         return True.
-
-        The optional argument *msg* is passed as the argument to the
-        asyncio.CancelledError exception raised when a cancelled Future
-        is awaited. It can be any object.
         """
         self.__log_traceback = False
         if self._state != _PENDING: