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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_status(self, status_code: int, reason: str = None) -> None: """Sets the status code for our response. :arg int status_code: Response status code. :arg str reason: Human-readable reason phrase describing the status code. If ``None``, it will be filled in from `http.client.responses` or "Unknown". .. versionchanged:: 5.0 No longer validates that the response code is in `http.client.responses`. """

        self._status_code = status_code
        if reason is not None:
            self._reason = escape.native_str(reason)
        else:
            self._reason = httputil.responses.get(status_code, "Unknown")