src/precore/util/Predicates.php
public static function in(Traversable $traversable) : callable
    {
        return function ($element) use ($traversable) {
            return Iterators::contains(Iterators::from($traversable), $element);
        };
    }
public static function in(Traversable $traversable) : callable
    {
        return function ($element) use ($traversable) {
            return Iterators::contains(Iterators::from($traversable), $element);
        };
    }
Returns true if the predicate parameter is contained by the given {@link Traversable}.

@param Traversable $traversable
@return callable