docstr: Returns a string that describes the type of driver
docstr_tok: ["Returns","a","string","that","describes","the","type","of","driver"]
code: def driver_type(self):
      """Returns a string that describes the type of driver"""
  
imports: from abc import abstractmethod, ABCMeta
  from streamalert.shared.logger import get_logger
label_desc: Use image node_id 2 for calling the PersistenceDriver obj's underlying member method code with example usage: obj.driver_type() without return types