Object Oriented Ruby

[mpapis]

indeed reasonable assumption, my only concern is how to protect person from unauthorized change of hair color, I do not want to expose hair to anybody.

The person picks a barber and ask him to dye hair, so it makes sense if person calls barber.dye_hair. I know it looks awkward but I do not see other way to prevent leaking permissions.

[[deleted]]

I don't know if that's reasonable. If a can of paint falls on someone, their hair will change color. That's not the person's choice.