code: def get_relation(self, relation):
          
          from .relations import Relation
  
          with Relation.no_constraints(True):
              rel = getattr(self.get_model(), relation)()
  
          nested = self._nested_relations(relation)
  
          if len(nested) > 0:
              rel.get_query().with_(nested)
  
          return rel
docs: Get the relation instance for the given relation name.
  
          :rtype: orator.orm.relations.Relation