code: def null_index(col: Column) -> Column:
      if is_remote():
          from pyspark.sql.connect.functions.builtin import (
              _invoke_function_over_columns,
          )
  
          return _invoke_function_over_columns(  # type: ignore[return-value]
              "null_index",
              col,  # type: ignore[arg-type]
          )
  
      else:
          sc = SparkContext._active_spark_context
          return Column(sc._jvm.PythonSQLUtils.nullIndex(col._jc))
  
file_path: spark/python/pyspark/pandas/spark/functions.py
imports: from pyspark import SparkContext
  from pyspark.sql.column import Column
  from pyspark.sql.utils import is_remote
label_desc: Use image node_id 9 for calling a global function with example usage: null_index(col) and returns: _invoke_function_over_columns, Column