docs: public final Constraint addConstraintsDebug(Constraint... c) {
  		ArrayList<Constraint> addedSoFar = new ArrayList<Constraint>(c.length);
  		for (Constraint con : c) {
  			if (!this.addConstraint(con)) {
  				this.removeConstraints(addedSoFar.toArray(new Constraint[addedSoFar.size()]));
  				return con;
  			}
  			else { addedSoFar.add(con); }
  		}
  		return null;
  	}