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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 flush(self, n=4096):
 """ Flush `n` bytes of data from the reader Stream to the writer Stream. Returns the number of bytes that were actually flushed. A return value of zero is not an error. If EOF has been reached, `None` is returned. """


        try:
            read = self.from_stream.read(n)

            if read is None or len(read) == 0:
                self.eof = True
                if self.propagate_close:
                    self.to_stream.close()
                return None

            return self.to_stream.write(read)
        except OSError as e:
            if e.errno != errno.EPIPE:
                raise e