Python Decorator to Time a Function

timer.py

""" A simple decorator that times the duration of a function's execution. More info on Decorators at https://pythonconquerstheuniverse.wordpress.com/2009/08/06/introduction-to-python-decorators-part-1/"""
import timeit

def timer(function):
  def new_function():
    start_time = timeit.default_timer()
    function()
    elapsed = timeit.default_timer() - start_time
    print('Function "{name}" took {time} seconds to complete.'.format(name=function.__name__, time=elapsed))
  return new_function()

@timer
def addition():
  total = 0
  for i in range(0,1000000):
    total += i
  return total

#
# Function "addition" took 0.081396356006735 seconds to complete.
#

As written it will call the decorated function on import.

This works for me only when I change line 10 from
return new_function()
to
return new_function

Yes, very true. Also this code can be improved in two ways:

1. Use the @wraps(new_function) decorator from functools (from functools import wraps) between line 4 and 5.
2. With this solution, the decorated function cannot have any arguments. Here is a better implementation: https://stackoverflow.com/a/51503837