code: def clean_stale_refs(self, local_refs=None):  # pylint: disable=arguments-differ
          '''
          Clean stale local refs so they don't appear as fileserver environments
          '''
          try:
              if pygit2.GIT_FETCH_PRUNE:
                  # Don't need to clean anything, pygit2 can do it by itself
                  return []
          except AttributeError:
              # However, only in 0.26.2 and newer
              pass
          if self.credentials is not None:
              log.debug(
                  'The installed version of pygit2 (%s) does not support '
                  'detecting stale refs for authenticated remotes, saltenvs '
                  'will not reflect branches/tags removed from remote \'%s\'',
                  PYGIT2_VERSION, self.id
              )
              return []
          return super(Pygit2, self).clean_stale_refs(f clean_stale_refs(self, local_refs=None):  # pylint: disable=arguments-differ
          '''
          Clean stale local refs so they don't appear as fileserver environments
          '''
          try:
              if pygit2.GIT_FETCH_PRUNE:
                  # Don't need to clean anything, pygit2 can do it by itself
                  return []
          except AttributeError:
              # However, only in 0.26.2 and newer
              pass
          if self.credentials is not None:
              log.debug(
                  'The installed version of pygit2 (%s) does not support '
                  'detecting stale refs for authenticated remotes, saltenvs '
                  'will not reflect branches/tags removed from remote \'%s\'',
                  PYGIT2_VERSION, self.id
              )
              return []
          return super(Pygit2, self).clean_stale_refs()
docs: Clean stale local refs so they don't appear as fileserver environments