def is_id(id_string):
 reg_ex = '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$'
 return bool(re.match(reg_ex, id_string))

def is_id ( id_string ) : reg_ex = '^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$' return bool ( re . match ( reg_ex , id_string ) )
tells the client if the string looks like a revision id or not .