python - unbound method must be called with instance as first argument -

i trying build simple fraction calculator in python2.x

from fractions import fraction class thefraction:      def __init__(self,a,b):         self.a =         self.b =b     def add(self):         return a+b     def subtract(self,a,b):         return a-b     def divide(self,a,b):         return a/b     def multiply(self,a,b):         return a/b  if __name__=='__main__':     try:         = fraction(input('please type first fraction '))         b = fraction(input('please type second fraction '))         choice = int(input('please select 1 of these 1. add 2. subtract 3. divide 4. multiply '))         if choice ==1:             print(thefraction.add(a,b))         elif choice==2:             print(thefraction.subtract(a,b))         elif choice==3:             print(thefraction.divide(a,b))         elif choice==4:             print(thefraction.multiply(a,b))     except valueerror:         print('value error!!!!!') 

i not sure made correct class can instantiated, used like,thefraction.add in side of __name__=='__main__'. did miss something?

it's meant done this:

thefraction = thefraction(a, b) if choice == 1:     print(thefraction.add()) 

then in class:

def add(self):     return self.a + self.b 

and on. don't include a , b parameters in methods.

and yes, go through tutorial on classes again. thoroughly.