code: function (error) {
              this.error = error;
              this.isRejected = true;
  
              if (this.parent === null) {
                  return;
              }
  
              this.parent.dispatch(this.name);
              this.parent.dispatch('reject', {
                  data : { node : this, error: error }
              });
          }
docs: method to notify that the step executed wrong.
  @property reject <public> [Function]