A function.
| arg | An instance of <string>. |
| arg | An instance of <string>. |
| start: | An instance of <integer>. The default is 0. |
| end: | An instance of type-union(<integer>, <false>). The default is #f. |
| case-sensitive: | An instance of <boolean>. The default is #f. |
| #rest more | Instances of <object>. |