code: def _nested_splitchars(x, encoding):
      """Replace each string in a nested list with a list of char substrings."""
      if isinstance(x, list):
          return [_nested_splitchars(v, encoding) for v in x]
      else:
          b = x.encode("utf-32-be")
          chars = zip(b[::4], b[1::4], b[2::4], b[3::4])
          if str is bytes:
              return [
                  b"".join(c).decode("utf-32-be").encode(encoding)
                  for c in chars
              ]
          else:
              return [
                  bytes(c).decode("utf-32-be").encode(encoding)
                  for c in chars
              ]
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import errors
  from tensorflow.python.framework import sparse_tensor
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_string_ops
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.ops.ragged import ragged_string_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling a global function with example usage: _nested_splitchars(x, encoding) and returns: unknown, unknown, unknown