def parse_cache_control_header(value, on_update=None, cls=None):
 if (cls is None):
  cls = RequestCacheControl
 if (not value):
  return cls(None, on_update)
 return cls(parse_dict_header(value), on_update)

def parse_cache_control_header ( value , on_update = None , cls = None ) : if ( cls is None ) : cls = RequestCacheControl if ( not value ) : return cls ( None , on_update ) return cls ( parse_dict_header ( value ) , on_update )
parse a cache control header .