in
https://docs.python.org/3.5/howto/descriptor.html#static-methods-and-class-methods

(same problem in all python 3.x documentations)

There is this example where the return of f function is printed and there is already a print in the function:
"""
>>> class E(object):
     def f(x):
          print(x)
     f = staticmethod(f)

>>> print(E.f(3))
3
>>> print(E().f(3))
3
"""

It should probably be:

"""
def f(x):
    return(x)
"""

or 

"""
>> E.f(3)
3
>> E().f(3)
"""