code: def test_warnings(self):
      pytest.warns(
          UserWarning,
          Image._apply_env_variables,
          {"PILLOW_ALIGNMENT": "15"},
      )
      pytest.warns(
          UserWarning,
          Image._apply_env_variables,
          {"PILLOW_BLOCK_SIZE": "1024"},
      )
      pytest.warns(
          UserWarning,
          Image._apply_env_variables,
          {"PILLOW_BLOCKS_MAX": "wat"},
      )
  
imports: import sys
  import pytest
  from PIL import Image
  from .helper import is_pypy
label_desc: Use image node_id 3 for calling the TestEnvVars obj's underlying member method code with example usage: obj.test_warnings() without return types