old_contents: #-*-coding:utf-8-*-
  
  from .cache import cache
  from .line import BusLine
  
  
  class BeijingBus(object):
  
      @classmethod
      def build_cache(cls):
          cache.invalidate(hard=True)
          cls.get_all_lines()
  
      @classmethod
      def get_all_lines(cls):
          return BusLine.get_all_lines()
  
      @classmethod
      def search_lines(cls, keyword):
          return list(BusLine.search(keyword))
  
new_contents: #-*-coding:utf-8-*-
  
  from .cache import cache
  from .line import BusLine
  
  
  class BeijingBus(object):
  
      @classmethod
      def build_cache(cls):
          cache.invalidate(hard=True)
          cls.get_all_lines()
  
      @classmethod
      def get_all_lines(cls):
          return BusLine.get_all_lines()
  
      @classmethod
      def search_lines(cls, keyword):
          return list(BusLine.search(str(keyword)))
  
subject: convert to str