This is a decorator for any sub function called in an OpenUpgrade script
(pre, post or end migration script).

Decorate functions that may take time. If a function is decorated, we
provide an iterable argument that will be looped on and call the original
function, while a progress bar will be displayed.

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:param index: Index of the argument to be used as iterable. Default to the
  second argument. It will pass each of the elements of the iterable in the
  same place.
:param title: Optional title for prefixing the progress bar. If not
  specified, the function name will be used.

Typical use::

@openupgrade.progress()
def migrate_some_stuff(env, record)
    # some custom code
    ...

@openupgrade.migrate()
def migrate(env, version):
    records = ...  # get an iterable
    migrate_some_stuff(env, records)

Co-Authored-By: Yann Papouin <[email protected]>