Use uppercase for global variables and lowercase for local variables

Use uppercase for global variables and lowercase for local variables 
NAME=[ ' cat ' , ' dog ' ]

def change_name():
    global NAME
    name='parrow'
    print('my name is ',name)
change_name()
print(NAME)

代码的执行步骤
1  NAME ='cloud'
   def huangwei():
 3   name='rain'
 4   print(name)
    def liuhai():
  6      name ="black"
   7     print(name)
        def muuli():
    10        name='white'
     11       print(name)
 8        print(name)
  9       muuli()
 5    liuhai()
 12 print(name)
2   huangwei()