docs: def load_all(self, key, default=None):
          '''
          Import settings key as a dict or list with values of importable paths
          If a default constructor is specified, and a path is not importable, it
          falls back to running the given constructor.
          '''
          value = getattr(self, key)
          if default is not None:
              def loader(path): return self.load_path_with_default(path, default)
          else:
              loader = self.load_path
          if isinstance(value, dict):
              return {key: loader(value) for key, value in value.items()}
          elif isinstance(value, list):
              return [loader(value) for value in value]
          else:
              raise ValueError('load_all must be list or dict')