Python define class functions in seperate py file -

i working on project deals data analysis. in order simplify process of finding , modifying functions, have decided put functions of similar purposes in different py files. issue comes in when functions in 1 py file require functions work. think can solve issue working class. demonstrate solution trying implement, have 3 files:

a.py

def a1(self):     self.var=3  def a2(self):     self.b1(4) 

b.py

def b1(self, x):     self.var=x  def b2(self):     self.a1() 

testclass.py

class test(object):     def __init__(self):         self.var=0      b import *     import *  a=test() print a.var a.a1() print a.var  a.a2() print a.var  a.b2() print a.var 

this want python unhappy me importing these 2 py files in fashion. in c++ prototype functions, forward declaration, , place definitions in file , have no issues. proper way define functions class in py file class definition not in?

use mix-in classes:

# in a.py class a(object):     def a1(self):         self.var=3      def a2(self):         self.b1(4)  # in b.py class b(object):     def b1(self, x):         self.var=x      def b2(self):         self.a1()   # in testclass.py class test(a, b):     def __init__(self):         self.var=0