code: def test_objectmapper(self):
      df = pdml.ModelFrame([])
      self.assertIs(df.kernel_ridge.KernelRidge, kr.KernelRidge)
  
imports: import sklearn.kernel_ridge
  import pandas_ml
  import pandas_ml.util.testing
label_desc: Use image node_id 1 for calling the TestKernelRidge obj's underlying member method code with example usage: obj.test_objectmapper() without return types