code: def from_settings(cls, settings=None, storage=None):
          
          if storage is None:
              storage = cls.DEFAULT_STORAGE
          return cls.from_storage(storage(settings=settings))
docs: Create from settings.
  
          Parameters
          ----------
          settings : `dict`, optional
              Settings (default: None).
          storage : `type`, optional
              Storage class (default: cls.DEFAULT_STORAGE)
  
          Returns
          -------
          `markovchain.Markov`