code: def from_camel_case(cc: str) -> str:
      return "".join(
          [str(c) if not c.isupper() else "_" + c.lower() for c in cc]
      )
  
imports: from typing import Any, List, Union
  from pyspark.ml.param.shared import HasInputCol, HasOutputCol, Param
  from pyspark.sql import DataFrame, SparkSession, functions, types
  from pyspark.sql.window import Window
label_desc: Use image node_id 2 for calling a global function with example usage: from_camel_case(cc) and returns: str