code: def _validate_padding(padding):
      """Verify correctness of `padding` argument."""
      padding_ = str(padding).upper()
      if padding_ in {"SAME", "VALID"}:
          return padding_
      raise ValueError(
          'Argument padding="{}" not recognized; must be one of '
          '{{"VALID", "SAME"}} (case insensitive).'.format(padding)
      )
  
imports: import tensorflow.compat.v2
  from tensorflow_probability.python.experimental.nn.util import utils
  from tensorflow_probability.python.internal import assert_util
  from tensorflow_probability.python.internal import dtype_util
  from tensorflow_probability.python.internal import prefer_static
label_desc: Use image node_id 4 for calling a global function with example usage: _validate_padding(padding) and returns: padding_