Modifies collection so that it no longer has a key equal to key. Equality is determined by collection’s key-test function.
The boolean return value will be #t if the key was present and removed, or #f if the key was not present and hence not removed.
open
| collection | An instance of <mutable-explicit-key-collection>. |
| key | An instance of <object>. |
| boolean | An instance of <boolean>. |