docs: def from_validated_yaml(cls, yaml_str, selectable, **kwargs):
          """Create a shelf using a yaml shelf definition.
  
          :param yaml_str: A string containing yaml ingredient definitions.
          :param selectable: A SQLAlchemy Table, a Recipe, or a SQLAlchemy
          join to select from.
          :return: A shelf that contains the ingredients defined in yaml_str.
          """
          obj = safe_load(yaml_str)
          return cls.from_config(obj, selectable, **kwargs)