def METHOD_NAME(self):
    key = self._load_private_key(self._private_key)
    now = int(time.time())
    token = jwt.JWT(
        header={"alg": "RS256"},
        claims={
            "iat": now,
            "exp": now + self.expiration_time,
            "iss": int(self.app_id),
        },
        algs=["RS256"],
    )
    token.make_signed_token(key)
    return token.serialize()