code: def test_save(self):
      temp = tempfile.mkdtemp()
      file_path = os.path.join(self.resource_path, "orca/data/csv")
      data_shard = bigdl.orca.data.pandas.read_csv(file_path)
      path = os.path.join(temp, "data.pkl")
      data_shard.save_pickle(path)
      shards = bigdl.orca.data.XShards.load_pickle(path)
      assert isinstance(shards, bigdl.orca.data.SparkXShards)
      shutil.rmtree(temp)
  
file_path: BigDL/python/orca/test/bigdl/orca/data/test_pandas_backend.py
imports: import os.path
  import shutil
  import pytest
  from unittest import TestCase
  import bigdl.orca.data
  import bigdl.orca.data.pandas
  from bigdl.orca import OrcaContext
  from bigdl.dllib.nncontext import *
label_desc: Use image node_id 7 for calling the TestXShardsPandasBackend obj's underlying member method code with example usage: obj.test_save() without return types