def METHOD_NAME(self, status=400):
    """Submit message and assert that it was accepted."""
    if self.headers is not None:
        self.requests_session.headers = self.headers
    response = self.requests_session.request(
        self.method,
        self.server + self.uri + ("" if not self.args else "?" + self.args),
        data=self.data,
    )
    assert response.status_code == status