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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def eventFilter(self, watchedObject, event):
 """ Deletes an item from an editable combobox when the delete or backspace key is pressed in the list of items, or when ctrl-delete or ctrl-back space is pressed in the line-edit. When the combobox is not editable the filter does nothing. """

        if self.comboBox.isEditable() and event.type() == QtCore.QEvent.KeyPress:
            key = event.key()
            if key in (Qt.Key_Delete, Qt.Key_Backspace):
                if (watchedObject == self._comboboxListView
                    or (watchedObject == self.comboBox
                        and event.modifiers() == Qt.ControlModifier)):

                    index = self._comboboxListView.currentIndex()
                    if index.isValid():
                        row = index.row()
                        logger.debug("Removing item {} from the combobox: {}"
                                     .format(row, self._comboboxListView.model().data(index)))
                        self.cti.removeValueByIndex(row)
                        self.comboBox.removeItem(row)
                        return True

        # Calling parent event filter, which may filter out other events.
        return super(ChoiceCtiEditor, self).eventFilter(watchedObject, event)