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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 set_combine_stderr(self, combine):
 """ Set whether stderr should be combined into stdout on this channel. The default is ``False``, but in some cases it may be convenient to have both streams combined. If this is ``False``, and `exec_command` is called (or ``invoke_shell`` with no pty), output to stderr will not show up through the `recv` and `recv_ready` calls. You will have to use `recv_stderr` and `recv_stderr_ready` to get stderr output. If this is ``True``, data will never show up via `recv_stderr` or `recv_stderr_ready`. :param bool combine: ``True`` if stderr output should be combined into stdout on this channel. :return: the previous setting (a `bool`). .. versionadded:: 1.1 """

        data = bytes()
        self.lock.acquire()
        try:
            old = self.combine_stderr
            self.combine_stderr = combine
            if combine and not old:
                # copy old stderr buffer into primary buffer
                data = self.in_stderr_buffer.empty()
        finally:
            self.lock.release()
        if len(data) > 0:
            self._feed(data)
        return old