Track 12 · Lesson 7 of 12

Context managers

Guarantee clean-up with the with statement: write __enter__ and __exit__, handle exceptions in __exit__, and use contextlib.contextmanager and suppress.

You will be able to

• Explain what the with statement guarantees and when __enter__ and __exit__ run
• Write a context manager class, including what __enter__ returns
• Decide in __exit__ whether an exception is suppressed or propagates
• Write a context manager as a generator with contextlib.contextmanager
• Use contextlib.suppress for an expected, harmless exception