code: def str_to_list(
      arg: Union[List[str], str], arg_name: str
  ) -> List[str]:
      if isinstance(arg, str):
          return [arg]
      invalidInputError(
          isinstance(arg, list),
          arg_name + " should be str or a list of str",
      )
      return arg
  
imports: from bigdl.dllib.utils.file_utils import callZooFunc
  from pyspark.sql.types import IntegerType, ShortType, LongType, FloatType, DecimalType, DoubleType, BooleanType
  from pyspark.sql.functions import broadcast, udf
  from bigdl.dllib.utils.log4Error import *
  import warnings
  from bigdl.dllib.utils.log4Error import *
  from typing import TYPE_CHECKING, Any, List, Optional, Tuple, Union
label_desc: Use image node_id 24 for calling a global function with example usage: str_to_list(arg, arg_name) and returns: arg, list