code: def setUpClass(cls):
      cls._stack = stack = ExitStack()
      cls.calendar = cal = date_range(
          "2014", "2015", freq="D", tz="UTC"
      )
      cls.sids = list(range(5))
      cls.engine = stack.enter_context(
          temp_pipeline_engine(
              cal,
              cls.sids,
              random_seed=100,
              symbols=chrange("A", "E"),
          ),
      )
      cls.assets = cls.engine._finder.retrieve_all(cls.sids)
  
file_path: catalyst/tests/pipeline/test_column.py
imports: from contextlib2 import ExitStack
  from unittest import TestCase
  from pandas import date_range, DataFrame
  from pandas.util.testing import assert_frame_equal
  from catalyst.lib.labelarray import LabelArray
  from catalyst.pipeline import Pipeline
  from catalyst.pipeline.data.testing import TestingDataSet
  from catalyst.testing import chrange, temp_pipeline_engine
  from catalyst.utils.pandas_utils import ignore_pandas_nan_categorical_warning
label_desc: Use image node_id 1 for calling the LatestTestCase obj's underlying member method code with example usage: obj.setUpClass(cls) without return types