code: def _is_variable(x):
      return isinstance(x, tf.Variable)
  
file_path: sonnet/sonnet/src/custom_getter.py
imports: from typing import Any, Callable, ContextManager, Iterable, Optional, Type
  import contextlib
  from sonnet.src import base
  import tensorflow
  import tree
label_desc: Use image node_id 4 for calling a global function with example usage: _is_variable(x) and returns: isinstance