Python: Cannot Assign Function Call -

i having problem such as:

def function (number):       number in list:           number = number + 1

for example function(1): number in range(1,5): number = number + 1

error come "can't assign function call" use variable value further calculations.

help!

i think have 2 problems. first, not naming function or declaring properly; should this:

def f(number):    ...

second, naming function parameter number on next line seem treating list though parameter. think mean instead:

def f(list):   number in my_list:   ...

Expalin