new_contents: #!/usr/bin/env python
  
  import contextlib, datetime
  
  @contextlib.contextmanager
  def timer(name='timer'):
      start = datetime.datetime.now()
      yield
      print('Elapsed time ({}): {}'.format(name, datetime.datetime.now() - start)) 
  
  if __name__ == '__main__':
      # measure the speed of two methods of dict creation
      with timer('dict = {}'):
          for _ in xrange(100000):
              d = {}
      with timer('dict = dict()'):  # takes almost twice as long as {}
          for _ in xrange(100000):
              d = dict()
  
subject: Create elapsed_time.py