- [ ] [is_empty](https://doc.rust-lang.org/std/string/struct.String.html#method.is_empty) - [ ] [starts_with](https://doc.rust-lang.org/std/string/struct.String.html#method.starts_with) - [ ] [ends_with](https://doc.rust-lang.org/std/string/struct.String.html#method.ends_with) - [ ] [contains](https://doc.rust-lang.org/std/string/struct.String.html#method.contains) / [matches](https://doc.rust-lang.org/std/string/struct.String.html#method.matches) (the latter for repetition counts)