import operator
     
     
def yoba(cls):

  	cls.C = [a + b for a in cls.A for b in cls.B]
  	return cls
    	
    	
@yoba
class Yoba:

    A = [1, 2, 3]
    B = [4, 5, 6]
        
     
y = Yoba()
print(Yoba.C)