py[BF] formula for nullevidence now better handles overflow
py[BF] formula for nullevidence now better handles overflow

esc/Psignifit-3.x,esc/Psignifit-3.x,esc/Psignifit-3.x,esc/Psignifit-3.x,esc/Psignifit-3.x,esc/Psignifit-3.x