code: def cdn_cache_control(val):
    
    if val is None:
      return 'max-age=3600, s-max-age=3600'
    elif type(val) is str:
      return val
    elif type(val) is bool:
      if val:
        return 'max-age=3600, s-max-age=3600'
      else:
        return 'no-cache'
    elif type(val) is int:
      if val < 0:
        raise ValueError('cdn_cache must be a positive integer, boolean, or string. Got: ' + str(val))
  
      if val == 0:
        return 'no-cache'
      else:
        return 'max-age={}, s-max-age={}'.format(val, val)
    else:
      raise NotImplementedError(type(val) + ' is not a supported cache_control setting.')
docs: Translate cdn_cache into a Cache-Control HTTP header.