code: def _next_tf_iterator(iterator, default=py_builtins.UNSPECIFIED):
      if default is py_builtins.UNSPECIFIED:
          # Without a default, fall back to the "normal" behavior which raises
          # a runtime exception.
          return next(iterator)
      opt_iterate = iterator.get_next_as_optional()
      _verify_structure_compatible(
          "the default argument",
          "the iterate",
          default,
          iterator.element_spec,
      )
      return cond.cond(
          opt_iterate.has_value(),
          opt_iterate.get_value,
          lambda: default,
      )
  
file_path: tensorflow-upstream/tensorflow/python/data/ops/iterator_autograph.py
imports: import functools
  import numpy
  from tensorflow.python.autograph.operators import control_flow
  from tensorflow.python.autograph.operators import py_builtins
  from tensorflow.python.data.ops import iterator_ops
  from tensorflow.python.framework import tensor_conversion
  from tensorflow.python.framework import tensor_spec
  from tensorflow.python.ops import cond
  from tensorflow.python.util import nest
label_desc: Use image node_id 3 for calling a global function with example usage: _next_tf_iterator(iterator, default) and returns: cond, next