foo = lambda x:x
Update : the answer may have something to do with this :
It’s possible to override the signature for explicitly documented callable
objects (functions, methods, classes) with the regular syntax that will
override the signature gained from introspection:
.. autoclass:: Noodle(type)
.. automethod:: eat(persona)
This is useful if the signature from the method is hidden by a decorator.
New in version 0.4.