Fix problem with py3.6 and test for quant2_int8_lstm (#41420) (#42447)

Co-authored-by: Njoanna.wozna.intel <joanna.wozna@intel.com>

python/paddle/distributed/parallel.py

@@ -30,6 +30,7 @@ from paddle.fluid.dygraph import parallel_helper
 from paddle.distributed.fleet.launch_utils import check_backend
 from paddle.fluid.dygraph.parallel import ParallelEnv
 from paddle.distributed.fleet.base.private_helper_function import wait_server_ready  # noqa: F401
+from paddle.distributed import collective
 from paddle.distributed.collective import _set_group_map
 from paddle.distributed.collective import _set_group_map_by_name
 from paddle.distributed.collective import _get_group_map_by_name

python/paddle/fluid/contrib/slim/tests/save_quant_model.py

@@ -88,8 +88,8 @@ def transform_and_save_int8_model(original_path,
                                   debug=False,
                                   quant_model_filename='',
                                   quant_params_filename='',
-                                  save_model_filename='',
-                                  save_params_filename=''):
+                                  save_model_filename="__model__",
+                                  save_params_filename=None):
     place = fluid.CPUPlace()
     exe = fluid.Executor(place)
     inference_scope = fluid.executor.global_scope()