code: def relations_to(self, target, include_object=False):
          ''' list all relations pointing at an object '''
          if include_object:
              _ = self._execute('''
                  select name, (select code from objects where id=src) from relations where dst=?
              ''', (self._id_of(target),))
              for i in _:
                  yield self.deserialize(i[1]), i[0]
          else:
              _ = self._execute('''
                  select distinct name from relations where dst=?
              ''', (self._id_of(target),))
              for i in _:
                  yield i[0f relations_to(self, target, include_object=False):
          ''' list all relations pointing at an object '''
          if include_object:
              _ = self._execute('''
                  select name, (select code from objects where id=src) from relations where dst=?
              ''', (self._id_of(target),))
              for i in _:
                  yield self.deserialize(i[1]), i[0]
          else:
              _ = self._execute('''
                  select distinct name from relations where dst=?
              ''', (self._id_of(target),))
              for i in _:
                  yield i[0]
docs: list all relations pointing at an object