code: public static <T, U> Predicate<Pair<T, U>> tupled(BiPredicate<T, U> predicate) {
          dbc.precondition(predicate != null, "cannot apply a pair to a null predicate");
          return pair -> predicate.test(pair.first(), pair.second());
      }
docs: Adapts a binary predicate to a predicate accepting a pair.
  
  @param <T> the predicate first parameter type
  @param <U> the predicate second parameter type
  @param predicate the predicate to be adapted
  @return the adapted predicate