Qt override.

def keyPressEvent(self, event):
        """
        Qt override.
        """
        if event.key() in [Qt.Key_Enter, Qt.Key_Return]:
            self._parent.process_text()
            if self._parent.is_valid():
                self._parent.keyPressEvent(event)
        else:
            QLineEdit.keyPressEvent(self, event)