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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 keyPressEvent(self, event):

 """Qt Override.
 
 Handle key press events.
 """

        if event.key() == Qt.Key_Return or event.key() == Qt.Key_Enter:
            if self.add_current_text_if_valid():
                self.selected()
                self.hide_completer()
        elif event.key() == Qt.Key_Escape:
            self.set_current_text(self.selected_text)
            self.hide_completer()
        else:
            QComboBox.keyPressEvent(self, event)