Report user error when "CC" is used in decay descriptor instead of "cc" for ParticleCombiner (Quality of life improvement)
After wondering why I did not see any candidates pass my selection with a decay descriptor as [D_s+ -> pi+ pi- pi+]CC
, I was pointed by a helpful colleague to the "CC" having to be "cc" for these decay descriptors.
While a silly mistake, I think it would be nice if we could throw the user a message that "CC" does not provide you with any candidates in the ParticleCombiner.