ssplit ket splits the ket into a sequence ssplit["str"] ket splits the ket into a sequence, splitting on str
ssplit |abcde> |a> . |b> . |c> . |d> . |e> ssplit[", "] |a, b, c> |a> . |b> . |c> ssplit[" and "] |a, b, c and d> |a, b, c> . |d> ssplit[", "] ssplit[" and "] |a, b, c and d> |a> . |b> . |c> . |d>