Validation - Cant make custom class with own validation rules

Hey,

I'm trying to make a validation class, like the one here: https://docs.phalcon.io/en/latest/reference/validation.html

But when i try to call the $validation = new MyValidation(); it says that the class can't be found..

Im trying to use my rules inside my model in the public function validate()

And also i dont know if this is the right category, sorry if not - Just couldent find any category with "Validation"

Sorry for my bad english :-)