code: def test_expand(self):
      expand = Expand(
          means_r=123, means_g=117, means_b=104, max_expand_ratio=2.0
      )
      self.transformer_test(expand)
  
imports: import pytest
  import os
  from bigdl.dllib.utils.common import *
  from bigdl.dllib.feature.transform.vision.image import *
  import tempfile
label_desc: Use image node_id 26 for calling the TestLayer obj's underlying member method code with example usage: obj.test_expand() without return types