code: function() {
      // If the user is on a valid value, then we increment the value, but if
      // they've typed something that's not right we page through predictions
      if (this.assignment.getStatus() === Status.VALID) {
        return this.requisition.nudge(this.assignment, 1).then(function() {
          this.textChanged();
          this.focusManager.onInputChange();
          return true;
        }.bind(this));
      }
  
      return Promise.resolve(false);
    }
docs: See also handleDownArrow for some symmetry