code: def relationship(self, node):
          
          self._check_node(node)
          my_rel = _rel_helper(lhs='us', rhs='them', ident='r', **self.definition)
          q = "MATCH " + my_rel + " WHERE id(them)={them} and id(us)={self} RETURN r LIMIT 1"
          rels = self.source.cypher(q, {'them': node.id})[0]
          if not rels:
              return
  
          rel_model = self.definition.get('model') or StructuredRel
  
          return self._set_start_end_cls(rel_model.inflate(rels[0][0]), node)
docs: Retrieve the relationship object for this first relationship between self and node.
  
          :param node:
          :return: StructuredRel