QAbstractItemModel & QTableView with more than one QStyledItemDelegateForColumn, crashes my app

from PySide2 import QtWidgets
from PySide2 import QtCore
from PySide2 import QtGui
import os
import PySide2
import sys
dirname = os.path.dirname(PySide2.__file__)
plugin_path = os.path.join(dirname, 'plugins', 'platforms')
os.environ['QT_QPA_PLATFORM_PLUGIN_PATH'] = plugin_path
alphabet = ["A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O"]
class IconDelegate(QtWidgets.QStyledItemDelegate):
    def initStyleOption(self, option, index):
        super(IconDelegate, self).initStyleOption(option, index)
        if option.features & QtWidgets.QStyleOptionViewItem.HasDecoration:
            s = option.decorationSize
            s.setWidth(option.rect.width())
            option.decorationSize = s
class Delegate(QtWidgets.QStyledItemDelegate):
    def __init__(self, parent=None):
        super(Delegate, self).__init__(parent=None)
    def initStyleOption(self, option, index):
        
#        super(IconDelegate, self).initStyleOption(option, index)
        if index.column() == 6:
            if option.features & QtWidgets.QStyleOptionViewItem.HasDecoration:
                s = option.decorationSize
                s.setWidth(option.rect.width())
                option.decorationSize = s
    def createEditor(self, parent, option, index):
        editor = QtWidgets.QComboBox(parent)         
        return editor
    def setEditorData(self, editor, index):
        model = index.model()
        items = model.items
        text = items[index.row()][index.column()]
        editor.setCurrentText(text)
    def setModelData(self, editor, model, index):
        
        items = model.items
#
class TableView(QtWidgets.QTableView):
    def __init__(self, parent=None):
        super(TableView, self).__init__(parent=None)
        delegate = Delegate()
        #Here is the place of bug. Please try the two cases.
        self.setItemDelegateForColumn(6, delegate)
        self.setItemDelegateForColumn(11, IconDelegate())
        self.tableModel = TableModel(2, 15)
        self.setModel(self.tableModel)
    def keyPressEvent(self, event):
        if event.key() == QtCore.Qt.Key_1:
            self.tableModel.insertRows(0)
            
class TableItem(object):
    def __init__(self,  parent=None):        
        self.root = False         self.word = ""
        self.alignment = QtCore.Qt.AlignCenter
        
        self.rule = ""
        self.foregroundcolor = QtGui.QColor(QtCore.Qt.black)
        self.backgroundcolor = QtGui.QColor(QtCore.Qt.white)
        self.font = QtGui.QFont("Meiryo", 14)
class TableModel(QtCore.QAbstractTableModel):
  
    def __init__(self, row = 0, column = 0, parent = None):
        super(TableModel, self).__init__(parent = None)        
        self.items = [[TableItem() for c in range(column)] for r in range(row)]
        self.root = QtCore.QModelIndex()        
    def rowCount(self, parent=QtCore.QModelIndex()):        
        return len(self.items)
    def columnCount(self, parent=QtCore.QModelIndex()):       
        return 15
    def data(self, index, role = QtCore.Qt.DisplayRole):    
        if not index.isValid():
            return None
        row = index.row()
        column = index.column()        
        if role == QtCore.Qt.DisplayRole:
            item = self.items[row][column]
            return item
    def headerData(self, section, orientation, role = QtCore.Qt.DisplayRole):
        if orientation == QtCore.Qt.Orientation.Horizontal:
            if role == QtCore.Qt.DisplayRole:
                return alphabet[section]
        return super(TableModel, self).headerData(section, orientation, role)
    def flags(self, index):        
        return QtCore.Qt.ItemFlag.ItemIsEditable|QtCore.Qt.ItemFlag.ItemIsEnabled|QtCore.Qt.ItemFlag.ItemIsSelectable
    def setData(self, index, value, role=QtCore.Qt.EditRole):        
        if role == QtCore.Qt.EditRole:       
            row, column = index.row(), index.column()
        
            self.items[row][column]  = value
            self.dataChanged.emit(index, index)
            return True
        elif role == QtCore.Qt.DisplayRole:             
            row, column = index.row(), index.column()
            self.items[row][column]  = value
            self.dataChanged.emit(index, index)
            return True
        elif role == QtCore.Qt.FontRole:
            string = value.toString()
            s = string.split(",")
            font = s[0]
            
            self.dataChanged.emit(index, index)
            return True
    def insertRows(self, position, rows=1, index=QtCore.QModelIndex()):   
        self.beginInsertRows(QtCore.QModelIndex(), position, position+rows-1)
        for row in range(rows):        
            self.items.insert(position+row, [TableItem() for c in range(self.columnCount())])
        self.endInsertRows()
        self.emit(QtCore.SIGNAL("dataChanged(QModelIndex, QModelIndex)"), index, index)
        self.emit(QtCore.SIGNAL("layoutChanged()"))      
        return True
    def removeRows(self, position, rows=1, index=QtCore.QModelIndex()):
        self.beginRemoveRows(QtCore.QModelIndex(), position, position+rows-1)
        for row in range(rows):
            self.items = self.items[:position] + \
                        self.items[position + rows:]
        self.emit(QtCore.SIGNAL("dataChanged(QModelIndex, QModelIndex)"), index, index)
        self.emit(QtCore.SIGNAL("layoutChanged()"))      
        return True
    
def main():
    if QtWidgets.QApplication.instance() is not None:
        app = QtWidgets.QApplication.instance()
    else:
        app = QtWidgets.QApplication([])
    mainwindow = TableView()
    mainwindow.show()
    sys.exit(QtWidgets.QApplication.exec_())
if __name__ == "__main__":
    main()