class A(object):
  def foo(self, x):
    print "executing foo(%s, %s)" % (self, x)
  @classmethod
  def class_foo(cls, x):
    print "executing class_foo(%s, %s)" % (cls, x)
  @staticmethod
  def static_foo(x):
    print "executing static_foo(%s)" % x  
a = A()
#通过实例调用方法，对象实例a作为第一个参数隐式传递。
a.foo (1)
# executing foo(<__main__.A object at 0xb7dbef0c>,1)
#对于类方法，对象实例的类将隐式地作为第一个参数而不是传递self
a.class_foo(1)
# executing class_foo(<class '__main__.A'>,1)
#使用这个类调用class_foo
A.class_foo(1)
# executing class_foo(<class '__main__.A'>,1)
#对于staticmethods,self(对象实例)和cls(类)都不会作为第一个参数隐式传递。它们的行为类似普通函数，除了你可以从实例或类中调用它们
a.static_foo(1)
# executing static_foo(1)
A.static_foo('hi')
# executing static_foo(hi)
print(a.foo)
# <bound method A.foo of <__main__.A object at 0xb7d52f0c
print(a.class_foo)
# <bound method type.class_foo of <class '__main__.A'
print(a.static_foo)
# <function static_foo at 0xb7d479cc>
print(a.static_foo)
# <function static_foo at 0xb7d479cc>