code: def add_mask_if_none(func, clip, *args, **kwargs):
      """Add a mask to the clip if there is none."""
      if clip.mask is None:
          clip = clip.add_mask()
      return func(clip, *args, **kwargs)
  
file_path: moviepy/moviepy/decorators.py
imports: import inspect
  import os
  import decorator
  from moviepy.tools import convert_to_seconds
label_desc: Use image node_id 11 for calling a global function with example usage: add_mask_if_none(func, clip) and returns: func