How to use the taurus.external.qt.Qt.QModelIndex function in taurus

    def rowCount(self, index=Qt.QModelIndex()):
        return len(self.curves)

def index(self, row, column, parent):
        if not parent.isValid():
            parentNode = self.root();
        else:
            parentNode = parent.internalPointer()
        childNode = parentNode.child(row)
        if childNode is None:
            return Qt.QModelIndex();
        else:
            return self.createIndex(row, column, childNode);

    def rowCount(self,index=Qt.QModelIndex()):
        return len(self.curves)

def expanded(self):
        for column in range(self.model().columnCount(Qt.QModelIndex())):
            self.resizeColumnToContents(column)

def parent(self, child):
        node = self.nodeFromIndex(child)
        if node is None:
            return Qt.QModelIndex()
        parent = node.parent()
        if parent is None:
            return Qt.QModelIndex()
        grandparent = parent.parent()
        if grandparent is None:
            return Qt.QModelIndex()
        row = grandparent.rowOfChild(parent)
        assert row != -1
        return self.createIndex(row, 0, parent)

def parent(self, child):
        node = self.nodeFromIndex(child)
        if node is None:
            return Qt.QModelIndex()
        parent = node.parent()
        if parent is None or isinstance(parent, macro.SequenceNode):
            return Qt.QModelIndex()
        grandparent = parent.parent()
        if grandparent is None:
            return Qt.QModelIndex()
        row = grandparent.rowOfChild(parent)
        return self.createIndex(row, 0, parent)

    def insertRows(self, position, rows=1, index=Qt.QModelIndex()):
        self.beginInsertRows(Qt.QModelIndex(), position, position + rows - 1)
        self.endInsertRows()

def setRangeForMacro(self, macroId, range):
        persistentIndex = self._idIndexDict.get(macroId, None)
        if persistentIndex is None:
            return
        index = Qt.QModelIndex(persistentIndex)
        node = self.model().nodeFromIndex(index)
        node.setRange(range)

def index(self, row, column=0, parent=Qt.QModelIndex()):
        if self.rowCount():
            return self.createIndex(row, column, self.list[row])
        else:
            return Qt.QModelIndex()

def removeRows(self, position, rows=1, index=Qt.QModelIndex()):
        self.beginRemoveRows(Qt.QModelIndex(), position, position+rows-1)
        self.endRemoveRows()