code: function(input) {
      // Deny RETURN unless the command might work
      if (this.requisition.status !== Status.VALID) {
        return Promise.resolve(false);
      }
  
      this.terminal.history.add(input);
      this.terminal.unsetChoice().catch(util.errorHandler);
  
      this.terminal._previousValue = this.terminal.inputElement.value;
      this.terminal.inputElement.value = '';
  
      return this.requisition.exec().then(function() {
        this.textChanged();
        return true;
      }.bind(this));
    }
docs: RETURN checks status and might exec