Creating a truth table for any expression in Python

I am attempting to create a program that when run will ask for the boolean expression, the variables and then create a truth table for whatever is entered. I need to use a class and this is what I have so far. I am not sure where to go from here.

from itertools import product

class Boolean(object):

       def __init__(self, statement, vars):
           self.exp = statement
           self.vars = vars

       def __call__(self, statement, vars):

def main():
   expression = raw_input('Give an expression:')
   vars = raw_input('Give names of variables:')
   variables = vars.split(' ')
   b = Boolean(expression, variables)

if __name__ == "__main__":
   main()