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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 __write_error(self, status_code, error_message=None):
 """Return the HTTP status line and body for a given error code and message. Args: status_code: HTTP status code to be returned. error_message: Error message to be returned. Returns: Tuple (http_status, body):
 http_status: HTTP status line, e.g. 200 OK. body: Body of the HTTP request. """

    if error_message is None:
      error_message = httplib.responses[status_code]
    status = '%d %s' % (status_code, httplib.responses[status_code])
    message = EndpointsErrorMessage(
        state=EndpointsErrorMessage.State.APPLICATION_ERROR,
        error_message=error_message)
    return status, self.__PROTOJSON.encode_message(message)