Takes a list and returns two lists: one that satisfies a predicate, and one that doesn’t. This is very much like choose, except this function also returns the elements that did not match the predicate.
| pred | An instance of <function>. |
| seq | An instance of <sequence>. |
| winners | An instance of <list>. The list of elements that satisfy pred. |
| losers | An instance of <list>. The list of elements that do not. |