For example, here's how you'd read a file in Python and operate on its contents.

  with open('file') as myfile:
      process(myfile.read())

When control leaves that context, `file.close()` is always called. You don't have to remember to close it. Even if `process()` raises an exception, the `with open` context will close it before passing the exception upward. You never have to remember to clean up the file yourself.

It's not that you can't do all that without context managers, obviously. People have done it for a long time. It's just that the `with open...` pattern is effectively bulletproof and removes just one more potential footgun.