accessing superclass methods from subclass

[ben]

Why doesn't this work:

class C1:
    def f1(self):
        print("f1")

class C2(C1):
    f1()


It throws this error:

Traceback (most recent call last):
  File "./c1.py", line 7, in <module>
    class C2(C1):
  File "./c1.py", line 8, in C2
    f1()
NameError: name 'f1' is not defined


f1() is an attribute of class C1, C2 inherits C1, so why can't it see
it?

thanks!