<prompt> Translate the following text to EnglishSura ya 31 inafafanua aagensi - chini ya mamlaka ya GAO - kwa njia pana sana, kumaanisha idara, shirika, au chombo cha serikali ya Marekani, lakini sio tawi la sheria au Mahakama Kuu.  <response>: Title 31 defines an aagency- subject to GAOas authority very expansively, to mean a adepartment, agency, or instrumentality- of the United States government, but not the legislative branch or the Supreme Court. 