python的静态方法、类方法与实例方法

a = 111
class A(object):
  a = 1

  def f_instance(self):
    print self.a

  @staticmethod
  def f_static():
    print a

  @classmethod
  def f_class(cls):
    print cls.a

aaa = A()
A.f_class               #1
A().f_class             #1
aaa.f_class            #1
A.f_static()            #111
A().f_static()          #111
aaa.f_static()         #111
A.f_instance()        # TypeError
A().f_instance()      #1
aaa.f_instance()     #1
f_static()               #NameError

aaa.a = 2
A.f_class()            #1
A().f_class()          #1
aaa.f_class()         #1
A.f_static()           #111
A().f_static()         #111
aaa.f_static()         #111
A.f_instance()       # TypeError
A().f_instance()     #1
aaa.f_instance()     #2
f_static()               #NameError


A().a = 2; aaa.a=1   #基于上一步的赋值
A.f_class()              #1
A().f_class()            #1
aaa.f_class()           #1
A.f_static()             #111
A().f_static()           #111
aaa.f_static()          #111
A.f_instance()         # TypeError
A().f_instance()       #1
aaa.f_instance()       #1
f_static()                #NameError



A.a = 10                 #基于上一步的赋值
A.f_class()              #10
A().f_class()            #10
aaa.f_class()            #10
A.f_static()              #111
A().f_static()            #111
aaa.f_static()           #111
A.f_instance()          # TypeError
A().f_instance()        #10
aaa.f_instance()        #1
f_static()                 #NameError