| QGIS API Documentation
    3.20.0-Odense (decaadbb31)
    | 
#include "qgsabstractrelationeditorwidget.h"#include "qgsfeatureiterator.h"#include "qgsexpression.h"#include "qgsfeature.h"#include "qgsfeatureselectiondlg.h"#include "qgsrelation.h"#include "qgsrelationmanager.h"#include "qgspolymorphicrelation.h"#include "qgsvectorlayertools.h"#include "qgsproject.h"#include "qgstransactiongroup.h"#include "qgsvectorlayerutils.h"#include <QMessageBox>#include <QPushButton>