Timing decorator is raising “'NoneType' object is not callable” exception

问题

I have i timing function and my main function. When i use only main function it runs fine, but when i use timing function as a decorator it raises an exception.

Timing function code:

def timing(function):
    import time
    t = time.time()
    function()
    t = time.time() - t
    print('Program has been running for {} seconds.'.format(t))

I use it like this:

@timing
def main():
    #some code

回答1:

The decorator needs to return the decorated function:

def timing(function):
  def wrapped():
    import time
    t = time.time()
    function()
    t = time.time() - t
    print('Program has been running for {} seconds.'.format(t))
  return wrapped

@timing
def main():
  # some code

来源：https://stackoverflow.com/questions/25877767/timing-decorator-is-raising-nonetype-object-is-not-callable-exception