code: def fetch(self, crc):
          
          cache_data = None
          pattern = '%08X.json' % crc
          hit = None
  
          for name in self._cache_files:
              if (name.endswith(pattern)):
                  hit = name
  
          if (hit):
              try:
                  cache = open(hit)
                  cache_data = json.load(cache,
                                         object_hook=self._decoder)
                  cache.close()
              except Exception as exp:
                  logger.warning('Error while parsing cache file [%s]:%s',
                                 hit, str(exp))
  
          return cache_data
docs: Try to get a hit in the cache, return None otherwise