class.py

class Force:
    def __init__(self,x,y):
        self.fx,self.fy=x,y
    def show(self):
        print('Force<%s,%s>' % (self.fx,self.fy))
    def add(self,force2):
        x=self.fx+force2.fx
        y=self.fy+force2.fy
        return Force(x,y)
    __add__=add
    '''def __add__(self,force2):
        x=self.fx+force2.fx
        y=self.fy+force2.fy
        return Force(x,y)'''
    

f1=Force(0,1)
f1.show()
f2=Force(3,4)
f3=f1.add(f2)
f3.show()
f3=f1+f2
f3.show()