function collect_all_even(collection) {

  return collection.filter(item => item%2 == 0);

}

function get_intersection(collection_a, collection_b) {
  return collection_b.filter(item => collection_a.includes(item))
}

function get_union(collection_a, collection_b) {

  return new Set([...collection_a,...collection_b]);

}

arr.sort((arr1, arr2) => arr1 - arr2)