code: public static <T1, T2, T3> TriPredicate<T1, T2, T3> not(TriPredicate<T1, T2, T3> predicate) {
          dbc.precondition(predicate != null, "cannot negate a null predicate");
          return predicate.negate();
      }
docs: Negates the given predicate.
  
  @param <T1> the first element type parameter
  @param <T2> the second element type parameter
  @param <T3> the third element type parameter
  @param predicate the predicate to be negated
  @return the negated predicate