custom key signature help

[James E. Bailey]

I don't understand custom key signatures. Why are the accidentals shown in the second measure? Do I have to set the key signature for each measure?

\version "2.12.2"

\relative c {

   \clef bass

   \time 5/4

   \set Staff.keySignature = #`(((-1 . 0) . ,SHARP) ((-1 . 3) . ,SHARP))

   cis4 d e fis g

   cis,4 d e fis g

}

James E. Bailey