Sort Multiple Columns Proxy

// multisort.h
#include <QSortFilterProxyModel>
#include <QList>
#include <QPair>
class MultySortProxy : public QSortFilterProxyModel
{
    Q_OBJECT
    Q_DISABLE_COPY(MultySortProxy)
public:
    explicit MultySortProxy(QObject *parent = nullptr);
    virtual ~MultySortProxy();
    void addSortPriority(int col, int role = Qt::DisplayRole);
    void revoveSortPriority(int col, int role = Qt::DisplayRole);
    void clearSortPriority();
    void insertSortPriority(int level, int col, int role = Qt::DisplayRole);
protected:
    virtual bool lessThan(const QModelIndex & source_left, const QModelIndex & source_right) const override;
protected:
    QList<QPair<int, int>> m_sortPriority;
};
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
// multisort.cpp
#include "multisort.h"
#include <QVariant>
MultySortProxy::MultySortProxy(QObject *parent)
    : QSortFilterProxyModel(parent)
{}

MultySortProxy::~MultySortProxy(){}

void MultySortProxy::addSortPriority(int col, int role)
{
    m_sortPriority.append(QPair<int, int>(col, role));
}

void MultySortProxy::revoveSortPriority(int col, int role)
{
    m_sortPriority.removeAt(m_sortPriority.indexOf(QPair<int, int>(col, role)));
}

void MultySortProxy::clearSortPriority()
{
    m_sortPriority.clear();
}

void MultySortProxy::insertSortPriority(int level, int col, int role)
{
    m_sortPriority.insert(level, QPair<int, int>(col, role));
}

bool MultySortProxy::lessThan(const QModelIndex & source_left, const QModelIndex & source_right) const
{
    for (auto i = m_sortPriority.constBegin(); i != m_sortPriority.constEnd();++i){
        const QVariant leftData = source_left.model()->index(source_left.row(), i->first, source_left.parent()).data(i->second);
        const QVariant rightData = source_right.model()->index(source_right.row(), i->first, source_right.parent()).data(i->second);
        if (leftData < rightData)
            return true;
        if (rightData < leftData)
            return false;
    }
    return false;
}