boolean set(NBTTagCompound data, String value, Player player) {
   String lower = value.toLowerCase();
   if ("true".startsWith(lower)) {
     data.setByte(_nbtKey, (byte) 1);
   } else if ("false".startsWith(lower)) {
     data.setByte(_nbtKey, (byte) 0);
   } else {
     return false;
   }
   return true;
 }
 String get(NBTTagCompound data) {
   if (data.hasKey(_nbtKey)) {
     return (data.getByte(_nbtKey) > 0 ? "true" : "false");
   }
   return null;
 }