code: def check_type(self, x, dtype):
      self.assertEqual(x.dtype, dtype)
      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 2 for calling the DummyInput obj's underlying member method code with example usage: obj.check_type(x, dtype) and returns: x