code: def apply_defaults(func: T) -> T:
      """
      Use apply_default decorator for the `default_args` feature to work properly; deprecated.
  
      In previous versions, all subclasses of BaseOperator must use apply_default decorator for the"
      `default_args` feature to work properly.
  
      In current version, it is optional. The decorator is applied automatically using the metaclass.
      """
      warnings.warn(
          "This decorator is deprecated. \n"
          "\n"
          "In previous versions, all subclasses of BaseOperator must use apply_default decorator for the "
          "`default_args` feature to work properly.\n"
          "\n"
          "In current version, it is optional. The decorator is applied automatically using the metaclass.\n",
          RemovedInAirflow3Warning,
          stacklevel=3,
      )
  
      # Make it still be a wrapper to keep the previous behaviour of an extra stack frame
      @wraps(func)
      def wrapper(*args, **kwargs):
          return func(*args, **kwargs)
  
      return cast(T, wrapper)
  
file_path: airflow/airflow/utils/decorators.py
imports: from __future__ import annotations
  import sys
  import warnings
  from collections import deque
  from functools import wraps
  from typing import Callable, TypeVar, cast
  from airflow.exceptions import RemovedInAirflow3Warning
label_desc: Use image node_id 1 for calling a global function with example usage: apply_defaults(func) and returns: cast, func