def __add__(self , Q):

    P , Q = self.standardise(Q)

    return Polynome( *[ P[i] + Q[i] for i in range( len(P) ) ] )

	

def __sub__(self , Q):

    P , Q = self.standardise(Q)

    return Polynome( *[ P[i] - Q[i] for i in range( len(self.coef) ) ] )