code: def _test() -> None:
      import doctest
      from pyspark.sql import SparkSession
      import pyspark.sql.udf
  
      globs = pyspark.sql.udf.__dict__.copy()
      spark = (
          SparkSession.builder.master("local[4]")
          .appName("sql.udf tests")
          .getOrCreate()
      )
      globs["spark"] = spark
      (failure_count, test_count) = doctest.testmod(
          pyspark.sql.udf,
          globs=globs,
          optionflags=doctest.ELLIPSIS | doctest.NORMALIZE_WHITESPACE,
      )
      spark.stop()
      if failure_count:
          sys.exit(-1)
  
imports: from inspect import getfullargspec
  import functools
  import inspect
  import sys
  import warnings
  from typing import Callable, Any, TYPE_CHECKING, Optional, cast, Union
  from py4j.java_gateway import JavaObject
  from pyspark import SparkContext
  from pyspark.rdd import _prepare_for_python_RDD, PythonEvalType
  from pyspark.sql.column import Column, _to_java_expr, _to_seq
  from pyspark.sql.types import DataType, StringType, StructType, _parse_datatype_string
  from pyspark.sql.utils import get_active_spark_context
  from pyspark.sql.pandas.types import to_arrow_type
  from pyspark.sql.pandas.utils import require_minimum_pandas_version, require_minimum_pyarrow_version
  from pyspark.errors import PySparkTypeError, PySparkNotImplementedError, PySparkRuntimeError
label_desc: Use image node_id 4 for calling a global function with example usage: _test() without return types