code: def _to_dense(
      sp_input, default_value=0, validate_indices=True, name=None
  ):  # pylint: disable=unused-argument
      if default_value != 0:
          raise NotImplementedError(
              "Argument `default_value != 0` is currently unimplemented."
          )
      if not validate_indices:
          raise NotImplementedError(
              "Argument `validate_indices != True` is currently unimplemented."
          )
      return sp_input
  
label_desc: Use image node_id 1 for calling a global function with example usage: _to_dense(sp_input, default_value, validate_indices, name) and returns: sp_input