code: def get_load_image_func(ext):
      callback = _get_callback("get_load_image_func")
      if callback:
          return callback.get_load_image_func(ext)
      else:
          return None
  
file_path: nnabla/python/src/nnabla/utils/callback.py
imports: from nnabla.config import nnabla_config
  import importlib
label_desc: Use image node_id 15 for calling a global function with example usage: get_load_image_func(ext) and returns: callback, None