Qt Override.

        Handle key press events.

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)