<prompt> Translate the following text to SwahiliUnder current conventions the Postal Service sets prices for whole subclasses and cannot select specific customers for surcharges or discounts.  <response>: Chini ya mikataba ya sasa Huduma ya Posta huweka bei kwa subclasses nzima na haiwezi kuchagua wateja maalum kwa ajili ya surcharges au punguzo. 