Improve process_letter method to handle multiple letters at a time
Improve process_letter method to handle multiple letters at a time

CompassionCH/compassion-modules,ecino/compassion-modules,ecino/compassion-modules,ecino/compassion-modules,eicher31/compassion-modules,eicher31/compassion-modules,maxime-beck/compassion-modules,CompassionCH/compassion-modules,CompassionCH/compassion-modules,eicher31/compassion-modules,maxime-beck/compassion-modules,CompassionCH/compassion-modules,eicher31/compassion-modules,ecino/compassion-modules,maxime-beck/compassion-modules,maxime-beck/compassion-modules,ecino/compassion-modules,eicher31/compassion-modules