code: public NotificationChain basicSetExpression(Expression newExpression, NotificationChain msgs)
    {
      Expression oldExpression = expression;
      expression = newExpression;
      if (eNotificationRequired())
      {
        ENotificationImpl notification = new ENotificationImpl(this, Notification.SET, SimpleExpressionsPackage.NOT_EXPRESSION__EXPRESSION, oldExpression, newExpression);
        if (msgs == null) msgs = notification; else msgs.add(notification);
      }
      return msgs;
    }
docs: <!-- begin-user-doc -->
  <!-- end-user-doc -->
  @generated