code: def translate(root_list, use_bag_semantics=False):
      
      translator = (Translator() if use_bag_semantics else SetTranslator())
      return [translator.translate(root).to_sql() for root in root_list]
docs: Translate a list of relational algebra trees into SQL statements.
  
      :param root_list: a list of tree roots
      :param use_bag_semantics: flag for using relational algebra bag semantics
      :return: a list of SQL statements