code: def test_warns_that_it_is_deprecated(self):
      children_fg = iaa.Identity()
      factor = 1
  
      with warnings.catch_warnings(record=True) as caught_warnings:
          warnings.simplefilter("always")
          _ = overlay.Alpha(factor, children_fg)
  
      assert len(caught_warnings) == 2
      assert "imgaug.augmenters.blend.BlendAlpha" in str(
          caught_warnings[0].message
      )
  
imports: from __future__ import print_function, division, absolute_import
  import warnings
  import sys
  import numpy
  import imgaug.augmenters
  import imgaug.augmenters.overlay
label_desc: Use image node_id 1 for calling the TestAlpha obj's underlying member method code with example usage: obj.test_warns_that_it_is_deprecated() without return types