A first look at python decorators (recommended)

#encoding: utf-8

############ contains a decorator #########
def outer(func):
  def inner(*args, **kwargs):# To decorate f1 (), here with these two formal parameters, can accept any parameter, regardless of f1 defined a few parameters
    print "1"
    r = func(*args, **kwargs)# Use func here, not f1.
    print "2"
    return r
  return inner

@outer # Don't put parentheses around this outer
def f1(a1, a2):
  print "a1 + a2 = "
  return a1 + a2

f1(1,2)

############ contains two decorators #########

def outer0(func):#First
  def inner(*args, **kwargs):
    print "AAAAAAAAA"
    r = func(*args, **kwargs)
    print "BBBBBBBB"
    return r
  return inner

def outer(func): #The second one #
  def inner(*args, **kwargs):# To decorate f1 (), here with these two formal parameters, can accept any parameter, regardless of f1 defined a few parameters
    print "1"
    r = func(*args, **kwargs)# Use func here, not f1.
    print "2"
    return r
  return inner
@outer0 # two decorators, the process is: the execution of f1(), first execute (), ().func call outer's inner function, that is, the () function as the argument to outer0.
     # Then ().func then calls f1()
@outer # Don't put parentheses around this outer
def f1(a1, a2):
  print "a1 + a2 = %d" %(a1+a2)
  return 1

f1(1,2)