Added docstring

Author: maushumee

pandas/core/groupby/groupby.py

@@ -4687,6 +4687,8 @@ def cumprod(self, numeric_only: bool = False, *args, **kwargs) -> NDFrameT:
 
         Parameters
         ----------
+        numeric_only : bool
+            Optional argument with default as False.
         *args : tuple
             Positional arguments to be passed to `func`.
         **kwargs : dict
@@ -4746,6 +4748,8 @@ def cumsum(self, numeric_only: bool = False, *args, **kwargs) -> NDFrameT:
 
         Parameters
         ----------
+        numeric_only : bool
+            Optional argument with default as False.
         *args : tuple
             Positional arguments to be passed to `func`.
         **kwargs : dict