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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, obj, event):
 """ Reimplemented to hide on certain key presses and on text edit focus changes. """

        if obj == self._text_edit:
            etype = event.type()

            if etype == QEvent.KeyPress:
                key = event.key()
                cursor = self._text_edit.textCursor()
                prev_char = self._text_edit.get_character(cursor.position(),
                                                          offset=-1)
                if key in (Qt.Key_Enter, Qt.Key_Return,
                           Qt.Key_Down, Qt.Key_Up):
                    self.hide()
                elif key == Qt.Key_Escape:
                    self.hide()
                    return True
                elif prev_char == ')':
                    self.hide()

            elif etype == QEvent.FocusOut:
                self.hide()

            elif etype == QEvent.Enter:
                if (self._hide_timer.isActive() and
                  self.app.topLevelAt(QCursor.pos()) == self):
                    self._hide_timer.stop()

            elif etype == QEvent.Leave:
                self._leave_event_hide()

        return super(CallTipWidget, self).eventFilter(obj, event)