docs: def add_options(cls, manager):
          """Register plug-in specific options."""
          kw = {}
          if flake8.__version__ >= '3.0.0':
              kw['parse_from_config'] = True
          manager.add_option(
              "--known-modules",
              action='store',
              default="",
              help=(
                  "User defined mapping between a project name and a list of"
                  " provided modules. For example: ``--known-modules=project:"
                  "[Project],extra-project:[extras,utilities]``."
              ),
              **kw
          )