context manager demo

context_man.py

from contextlib import contextmanager

@contextmanager
def manage_something(something):
  """ this is the general structure of a contextmanager """
  try:
    # prepare the something
    yield something
    
  except Exception as e:
    # do something when an error occurs, such as rollback some changes or close a connection
    # now raise the exception that caused the error (or maybe handle it instead!)
    raise e
  finally:
    # finalize something, such as close a connection or commit some database changes
    pass
  
  
if __name__ == "__main__":
  with manage_something(my_something) as this_thing:
    # do some stuff
    this_thing.foo()