code: def is_tf_optimizer(optimizer):
      return isinstance(optimizer, WrappedTFOptimizer)
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from sonnet.src import base
  from sonnet.src import test_utils
  import tensorflow
  import tree
label_desc: Use image node_id 1 for calling a global function with example usage: is_tf_optimizer(optimizer) and returns: isinstance