private <T>boolean addToListInternal(Collection<T> list,T value){
  if (!list.contains(value)) {
    list.add(value);
    isModified=true;
    return true;
  }
 else {
    return false;
  }
}

private < T > boolean addToListInternal ( Collection < T > list , T value ) { if ( ! list . contains ( value ) ) { list . add ( value ) ; isModified = true ; return true ; } else { return false ; } }
add a value to given list , making the project modified if the value is not already present in the list .
