Nope. I use this for `Negative::BOUNDARY` and the `BOUNDARY` constant is not inheritable, so `Number\Negative::BOUNDARY` does not explicitly exist. `$this::BOUNDARY` would, but to access that I'd need to add a getter to the `Number\Negative` and `Number\Positive` validators, which I'm a bit against, as they would only serve my unit test. I never knew that constants did not inherit like this, up until this test failed for that very reason.