code: def test_split(self):
      file_path = os.path.join(self.resource_path, "orca/data/csv")
      data_shard = bigdl.orca.data.pandas.read_csv(file_path)
      trans_data_shard = data_shard.transform_shard(
          lambda df: (df[0:-1], df[-1:])
      )
      assert (
          trans_data_shard.is_cached()
      ), "trans_data_shard should be cached"
      shards_splits = trans_data_shard.split()
      assert (
          not trans_data_shard.is_cached()
      ), "shards_splits should be uncached"
      trans_data_shard.uncache()
      del trans_data_shard
      assert len(shards_splits) == 2
      assert shards_splits[
          0
      ].is_cached(), "shards in shards_splits should be cached"
      data1 = shards_splits[0].collect()
      data2 = shards_splits[1].collect()
      assert len(data1[0].index) > 1
      assert len(data2[0].index) == 1
  
imports: import os.path
  import pytest
  from unittest import TestCase
  import bigdl.orca.data
  import bigdl.orca.data.pandas
  from bigdl.orca.data import SharedValue
  from bigdl.dllib.nncontext import *
  from bigdl.orca.data.transformer import *
  from bigdl.orca import init_orca_context
label_desc: Use image node_id 6 for calling the TestSparkXShards obj's underlying member method code with example usage: obj.test_split() without return types