docs: def get_class_from_settings(settings_key):
      """Gets a class from a setting key.  This will first check loaded models,
      then look in installed apps, then fallback to import from lib.
  
      :param settings_key: the key defined in settings to the value for
      """
      cls_path = getattr(settings, settings_key, None)
      if not cls_path:
          raise NotImplementedError()
  
      try:
          # First check to see if it's an installed model
          return get_model_from_settings(settings_key=settings_key)
      except:
          try:
              # Next, check from installed apps
              return get_class_from_settings_from_apps(settings_key=settings_key)
          except:
              # Last, try to load from the full path
              return get_class_from_settings_full_path(settings_key)