用PyQt5隐藏QtableView的QComboBox中已经选择的值

我有一个带有QComboBox小部件的表视图。所有的QComboBox都有相同的初始值,但是一旦选择了一个值,就必须将其从表中QComboBox的其余部分中删除。有可能吗?

我有一个信号,当文本在QComboBox中更改时,它会保存在一组使用过的字母中。因此,我需要从表视图中QComboBox的其余部分删除该字母。

我的代码如下:

from PyQt5.QtWidgets import QWidget, QComboBox
from PyQt5.QtGui import QStandardItemModel, QStandardItem

class widgetTabContent(QWidget, Ui_widgetTabContent):

    def __init__(self, parent=None):

        super(widgetTabContent, self).__init__(parent)
        self.setupUi(self)
        self.QSModel = QStandardItemModel()
        self.tvColumns.setModel(self.QSModel)
        self.letters = []

        self.cb_letters_used = set()
        self.fill_table()

    def combobox_current_text_changed(self, text):

        print(text)
        if text:
            self.cb_letters_used.add(text)
        print(self.cb_letters_used)
        # Commented this code as it becomes logically recursive

#        self.cb_update_list = [letter for letter in self.letters
#                            if letter not in self.cb_letters_used]
#        for row in range(self.QSModel.rowCount()):
#            self.tvColumns.indexWidget(self.tvColumns.model().index(row, 0)).clear()
#            self.tvColumns.indexWidget(self.tvColumns.model().index(row, 0)).addItems(self.cb_update_list)

    def fill_table(self):
         self.letters = ['A','B','C','D','E','F','G']
         self.QSModel.setColumnCount(1)
         for row in range(len(self.col_letters)):
             combobox = QComboBox()
             combobox.add_items(self.col_letters)
             combobox.currentTextChanged.connect(self.combobox_current_text_changed)
             self.QSModel.insertRow(row)
             self.tvColumns.setIndexWidget(self.tvColumns.model().index(row, 0), combobox)