code: def get_relation(self, rel_id, resolve_missing=False):
          
          relations = self.get_relations(rel_id=rel_id)
          if len(relations) == 0:
              if resolve_missing is False:
                  raise exception.DataIncomplete("Resolve missing relations is disabled")
  
              query = ("\n"
                       "[out:json];\n"
                       "relation({relation_id});\n"
                       "out body;\n"
                       )
              query = query.format(
                  relation_id=rel_id
              )
              tmp_result = self.api.query(query)
              self.expand(tmp_result)
  
              relations = self.get_relations(rel_id=rel_id)
  
          if len(relations) == 0:
              raise exception.DataIncomplete("Unable to resolve requested reference")
  
          return relations[0]
docs: Get a relation by its ID.
  
          :param rel_id: The relation ID
          :type rel_id: Integer
          :param resolve_missing: Query the Overpass API if the relation is missing in the result set.
          :return: The relation
          :rtype: overpy.Relation
          :raises overpy.exception.DataIncomplete: The requested relation is not available in the result cache.
          :raises overpy.exception.DataIncomplete: If resolve_missing is True and the relation can't be resolved.