code: public static <S extends Sequence<C>, C extends Compound> int getGCGChecksum(List<S> sequences) {
  		int check = 0;
  		for (S as : sequences) {
  			check += getGCGChecksum(as);
  		}
  		return check % 10000;
  	}
docs: Calculates GCG checksum for entire list of sequences
  
  @param sequences list of sequences
  @return GCG checksum