code: def check_type_structure(self, _, dtype):
      # pylint: disable=g-generic-assert
      tree.map_structure(
          lambda y: self.assertTrue(y.dtype == dtype), self.x
      )
      return self.x
  
imports: from absl.testing import parameterized
  from sonnet.src import base
  from sonnet.src import mixed_precision
  from sonnet.src import test_utils
  import tensorflow
  import tree
label_desc: Use image node_id 3 for calling the DummyVar obj's underlying member method code with example usage: obj.check_type_structure(_, dtype) and returns: self