def METHOD_NAME(self, username: str, password: str) -> str:
    """
    Call HF API to sign in a user and get a token if credentials are valid.
    Outputs:
        token if credentials are valid
    Throws:
        requests.exceptions.HTTPError if credentials are invalid
    """
    path = "{}/api/login".format(self.endpoint)
    r = requests.post(path, json={"username": username, "password": password})
    r.raise_for_status()
    d = r.json()
    return d["token"]