your question as already been answered here:
Python: defining my own operators?
A little addition to what was said on that tread would be that if you define custom objects then you can define the effect of an operator between two objects of the same type:
class Complex:
def __init__(self,real,imaginary):
self.real=real
self.imaginary= imaginary
def __add__(var):
c=Complex(self.real + var.real,self.imaginary +v.imaginary)
return c
This code snippet is a common example that creates a class that describes complex numbers and allowes you to do Complex_c=Complex_a+Complex_b
store the complex sum in Complex_c