def _validate_nbf(self, payload, now, leeway):
        try:
            nbf = int(payload['nbf'])
        except __HOLE__:
            raise DecodeError('Not Before claim (nbf) must be an integer.')

        if nbf > (now + leeway):
            raise ImmatureSignatureError('The token is not yet valid (nbf)')
dataset/ETHPy150Open jpadilla/pyjwt/jwt/api_jwt.py/PyJWT._validate_nbf