docstr: This test checks on output stateful (default) and stateless variants of ClassyBlock
  by enabling and propagating the environmental variable CLASSY_BLOCK_STATELESS
code: def setUp(self):
      """
      This test checks on output stateful (default) and stateless variants of ClassyBlock
      by enabling and propagating the environmental variable CLASSY_BLOCK_STATELESS
      """
      # initialize stateful model
      self._model_stateful = ClassyBlock(
          name="stateful", module=torch.nn.Identity()
      )
      # initialize stateless model
      os.environ["CLASSY_BLOCK_STATELESS"] = "1"
      self._model_stateless = ClassyBlock(
          name="stateless", module=torch.nn.Identity()
      )
      # note: use low=1 since default of ClassyBlock output variable is torch.zeros
      self._data = torch.randint(low=1, high=5, size=(3, 5, 5))
  
file_path: ClassyVision/test/models_classy_block_stateless_test.py
imports: import os
  import unittest
  import torch
  from classy_vision.models import ClassyBlock
label_desc: Use image node_id 1 for calling the TestClassyStatelessBlock obj's underlying member method code with example usage: obj.setUp() without return types