code: def str_to_list(arg, arg_name):
      if isinstance(arg, str):
          return [arg]
      assert isinstance(arg, list), (
          arg_name + " should be str or a list of str"
      )
      return arg
  
imports: from zoo.common.utils import callZooFunc
  from pyspark.sql.types import IntegerType, ShortType, LongType, FloatType, DecimalType, DoubleType
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