Subclassing with fewer keystrokes

Question

How can I define a subclass using an instance of the superclass without typing a lot? See:

class A():
    def __init__(self,x,y):
        self.x=x
        self.y=y

class B(A):
    def __init__(self,x,y,z):
        A.__init__(A,x,y)
        self.z=z

class1=A(2,3)
class2=B(class1.x,class1.y,5)   # Is there something easier than this, where I don't have to type class1.x, class1.y and
                                # I can just pass all the data members of class1 at once?

Answer 1

class A(object):
    def __init__(self,x,y):
        self.x=x
        self.y=y

class B(A):
    def __init__(self,a,z):
        self.a=a
        self.z=z

class1=A(2,3)
class2=B(class1,5)