code: public static List<MutableIntTuple> deepCopy(
          Collection<? extends IntTuple> tuples)
      {
          List<MutableIntTuple> result = 
              new ArrayList<MutableIntTuple>(tuples.size());
          for (IntTuple t : tuples)
          {
              if (t == null)
              {
                  result.add(null);
              }
              else
              {
                  result.add(IntTuples.copy(t));
              }
          }
          return result;
      }
docs: Returns a deep copy of the given collection of tuples. If any element
  of the given collection is <code>null</code>, then <code>null</code>
  will also be added to the target collection.
  
  @param tuples The input tuples
  @return The deep copy