code: def test_categorical(self):
      choices = ["a", "b", "c", "d"]
      param = space.Categorical(*choices)
      assert param.cs
      assert param.rand in choices
      assert param.default in choices
  
file_path: BigDL/python/nano/test/automl/common/test_space.py
imports: import pytest
  import os
  from unittest import TestCase
  import bigdl.nano.automl.hpo.space
label_desc: Use image node_id 1 for calling the TestHPOSpace obj's underlying member method code with example usage: obj.test_categorical() without return types