code: def as_string(s):
      return s
  
imports: from absl.testing import parameterized
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import gen_string_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 1 for calling a global function with example usage: as_string(s) and returns: s