QTextTable insertColumns fails at rowSpan > 1.

from PySide2 import QtGui
from PySide2 import QtCore
from PySide2 import QtWidgets
import sys, os
import PySide2
#Bug If you merge cells at all columns, and insertColumns, application falls.
class TextEdit(QtWidgets.QTextEdit):    
    def __init__(self, parent=None):        
        super(TextEdit, self).__init__(parent=None)            
    def keyPressEvent(self, event):        
        if event.key() == QtCore.Qt.Key_0:            
            tc = self.textCursor()            
            columnwidthconstraints = [QtGui.QTextLength(QtGui.QTextLength.VariableLength, 100) for i in range(3)]            
            tableformat = QtGui.QTextTableFormat()            
            tableformat.setColumnWidthConstraints(columnwidthconstraints)            
            tableformat.setWidth(300)            
            tc.insertTable(3, 3, tableformat)            
            return        
        if event.key() == QtCore.Qt.Key_1:            
            tc = self.textCursor()            
            currentTable = tc.currentTable()            
            if currentTable is not None:                
                currentTable.mergeCells(tc)            
                return        
        if event.key() == QtCore.Qt.Key_2:            
            tc = self.textCursor()            
            currentTable = tc.currentTable()            
            if currentTable is not None:                
                cell = currentTable.cellAt(tc)                
                currentTable.insertColumns(cell.column(), 1)            
                return        
        return QtWidgets.QTextEdit.keyPressEvent(self, event)
def main():    
    QtWidgets.QApplication([])    
    t = TextEdit()    
    t.setGeometry(300, 300, 500, 100)    
    t.show()    
    sys.exit(QtWidgets.QApplication.exec_())
if __name__ == "__main__":    
    main()