python.Function: match untuplify usage in id to the original

Signed-off-by: Eli Sennesh <sennesh.e@northeastern.edu>

Author: Eli Sennesh

discopy/python.py

@@ -171,9 +171,9 @@ def id(dom: Ty) -> Function:
         The identity function on a given tuple of types :code:`dom`.
 
         Parameters:
-            dom (python.Ty) : The typle of types on which to take the identity.
+            dom (python.Ty) : The tuple of types on which to take the identity.
         """
-        return Function(untuplify, dom, dom)
+        return Function(lambda *xs: untuplify(xs), dom, dom)
 
     def then(self, other: Function) -> Function:
         """