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The timer() context manager

A colleague of yours is working on a web service that processes Instagram photos. Customers are complaining that the service takes too long to identify whether or not an image has a cat in it, so your colleague has come to you for help. You decide to write a context manager that they can use to time how long their functions take to run.

This exercise is part of the course

Writing Functions in Python

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Exercise instructions

  • Add a decorator from the contextlib module to the timer() function that will make it act like a context manager.
  • Send control from the timer() function to the context block.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Add a decorator that will make timer() a context manager
@contextlib.____
def timer():
  """Time the execution of a context block.

  Yields:
    None
  """
  start = time.time()
  # Send control back to the context block
  ____
  end = time.time()
  print('Elapsed: {:.2f}s'.format(end - start))

with timer():
  print('This should take approximately 0.25 seconds')
  time.sleep(0.25)
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