code: def recycle():
      
      # http://niwinz.github.io/django-redis/latest/#_scan_delete_keys_in_bulk
      for service in cache.iter_keys('th_*'):
          try:
              # get the value from the cache version=2
              service_value = cache.get(service, version=2)
              # put it in the version=1
              cache.set(service, service_value)
              # remote version=2
              cache.delete_pattern(service, version=2)
          except ValueError:
              pass
      logger.info('recycle of cache done!')
docs: the purpose of this tasks is to recycle the data from the cache
          with version=2 in the main cache