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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 close(self):
 """ Close this pipe object. Future calls to `read` after the buffer has been emptied will return immediately with an empty string. """

        self._lock.acquire()
        try:
            self._closed = True
            self._cv.notifyAll()
            if self._event is not None:
                self._event.set()
        finally:
            self._lock.release()