code: def check_type_structure(self, x, dtype):
      tree.map_structure(lambda y: self.assertEqual(y.dtype, dtype), x)
      return 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 DummyInput obj's underlying member method code with example usage: obj.check_type_structure(x, dtype) and returns: x