code: def rand_string(length):
      import random
      import string
  
      """Generate a random string of fixed length """
      letters = string.ascii_lowercase
      return "".join(random.choice(letters) for _ in range(length))
  
imports: import logging
  from typing import List, Optional, Tuple
  from pyspark.sql.functions import col, crc32, explode, map_keys, udf
  from pyspark.sql.types import ArrayType, BooleanType, FloatType, LongType, MapType, StructField, StructType
  from reagent.data.data_fetcher import DataFetcher
  from reagent.data.spark_utils import get_spark_session, get_table_url
  from reagent.workflow.types import Dataset, TableSpec
label_desc: Use image node_id 19 for calling a global function with example usage: rand_string(length) and returns: str