code: def _is_running_on_cpu():
      """Returns True if the current context is CPU model."""
      return tpu_function.get_tpu_context().number_of_shards is None
  
imports: import math
  from tensorflow.python.feature_column import feature_column
  from tensorflow.python.feature_column import feature_column_lib
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import init_ops
  from tensorflow.python.ops import variable_scope
  from tensorflow.python.tpu import tpu
  from tensorflow.python.tpu import tpu_function
  from tensorflow.python.tpu import tpu_replication
label_desc: Use image node_id 4 for calling a global function with example usage: _is_running_on_cpu() and returns: unknown