#!/usr/bin/python

class X:
  def fn1(self):
    print("fn1")

  def fn2():
    print("fn2")

  def __init__(self):
    self.value = 99


x = X()   # OK
x.fn1()   # OK
X.fn1(x)  # OK
#X.fn1()  # TypeError: fn1() missing 1 required positional argument: 'self'
#x.fn2()  # TypeError: fn2() takes 0 positional arguments but 1 was given
X.fn2()   # OK in 3.2, 2.7: TypeError: unbound method fn2() must be called with X instance as first argument (got nothing instead)