code: def _decode_token_json(token):
      
      header, payload, raw_signatures, signing_inputs = _unpack_token_json(token)
      token = {
          'header': header,
          'payload': payload,
          'signature': [base64url_encode(rs) for rs in raw_signatures]
      }
      return token
docs: Decode a JSON-serialized JWT
      Returns {'header': ..., 'payload': ..., 'signature': ...}