<prompt> Translate the following text to EnglishKwa mfano, uhalali wa mkataba unaweza kutegemea kama mkataba umekubaliwa na kutekelezwa bila uchunguzi wowote wa kisheria, au badala yake umewasilishwa kwa aina fulani ya ukaguzi na Tume ya Kiwango cha Posta kabla ya ufanisi wake.  <response>: For example, the legality of an agreement may be dependent on whether the contract is agreed upon and performed without any regulatory scrutiny, or instead submitted for some form of review by the Postal Rate Commission prior to its effectiveness. 