<prompt> Translate the following text to EnglishMkataba wa Usalama wa Umma Usalama wa Umma ni mkataba wa usalama wa umma unaoidhinishwa na Mkurugenzi wa Idara ya Usalama wa Umma anayehusika na Usalama wa Umma.  <response>: an extended voluntary negotiation period obtain a certification confirming their public safety status from the department head responsible for system oversight. 