code: def to_gremlin(self):
          
          self.validate()
          template_data = {
              'direction': self.direction,
              'edge_name': self.edge_name,
              'inverse_direction': 'in' if self.direction == 'out' else 'out'
          }
          return (u'collectMany{{entry -> entry.{direction}_{edge_name}'
                  u'.collect{{edge -> edge.{inverse_direction}V.next()}}}}'
                  .format(**template_data))
docs: Return a unicode object with the Gremlin representation of this block.