| ⇢ | A | Collection::unshift() added | |
| ⇢ | A | Collection::push() added | |
| ⇢ | A | Collection::split() added | |
| ⇢ | A | Collection::diff() added | |
| ⇢ | A | Collection::kdiff() added | |
| ⇢ | A | Collection::intersect() added | |
| ⇢ | A | Collection::kintersect() added | |
| ⇢ | A | Collection::pop() added | |
| ⇢ | A | Collection::shift() added | |
| A | ↘ | B | Collection::contains() got worse |