code: def enclosing_tpu_context_and_graph():
      """Returns the TPUReplicateContext which exists inside a tpu.rewrite(), and its associated graph."""
      graph = ops.get_default_graph()
      while graph is not None:
          ctx = (
              graph._get_control_flow_context()
          )  # pylint: disable=protected-access
          while ctx is not None:
              if isinstance(ctx, tpu_replication.TPUReplicateContext):
                  return ctx, graph
              ctx = ctx.outer_context
          # This may be a FuncGraph due to defuns or v2 control flow. We need to
          # find the original graph with the XLAControlFlowContext.
          graph = getattr(graph, "outer_graph", None)
      return None, None
  
imports: import contextlib
  from tensorflow.python.distribute import packed_distributed_variable
  from tensorflow.python.eager import context
  from tensorflow.python.eager import def_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import resource_variable_ops
  from tensorflow.python.tpu import tpu_replication
label_desc: Use image node_id 2 for calling a global function with example usage: enclosing_tpu_context_and_graph() and returns: None,  None, ctx,  graph