code: def relation_clear(r_id=None):
      ''' Clears any relation data already set on relation r_id '''
      settings = relation_get(rid=r_id,
                              unit=local_unit())
      for setting in settings:
          if setting not in ['public-address', 'private-address']:
              settings[setting] = None
      relation_set(relation_id=r_id,
                   **settingsf relation_clear(r_id=None):
      ''' Clears any relation data already set on relation r_id '''
      settings = relation_get(rid=r_id,
                              unit=local_unit())
      for setting in settings:
          if setting not in ['public-address', 'private-address']:
              settings[setting] = None
      relation_set(relation_id=r_id,
                   **settings)
docs: Clears any relation data already set on relation r_id