code: def null_of(data_type: DataType) -> Expression:
      """
      Returns a null literal value of a given data type.
      """
      return _unary_op("nullOf", _to_java_data_type(data_type))
  
imports: from typing import Union
  from pyflink import add_version_doc
  from pyflink.java_gateway import get_gateway
  from pyflink.table.expression import Expression, _get_java_expression, TimePointUnit, JsonOnNull
  from pyflink.table.types import _to_java_data_type, DataType
  from pyflink.table.udf import UserDefinedFunctionWrapper
  from pyflink.util.java_utils import to_jarray, load_java_class
label_desc: Use image node_id 44 for calling a global function with example usage: null_of(data_type) and returns: _unary_op