code: def list_extensions():
      """
      List up available extensions.
  
      Note:
          It may not work on some platforms/environments since it depends
          on the directory structure of the namespace packages.
  
      Returns: list of str
          Names of available extensions.
  
      """
      import nnabla_ext.cpu
      from os.path import dirname, join, realpath
      from os import listdir
  
      ext_dir = realpath((join(dirname(nnabla_ext.cpu.__file__), "..")))
      return listdir(ext_dir)
  
label_desc: Use image node_id 2 for calling a global function with example usage: list_extensions() and returns: listdir