Incorrect document of "mixins clonable"?

[dram]

Document of mixins clonable seems to be incorrect:

This is the traits for ordinary objects. Ordinary objects are mutable and can be copied (cloned). A child should provide a methods for = and hash if the child is to be stored in a set or used as the key of a dictionary; the default is for objects to be compared and hashed using object identity.

Firstly, its a mixin, not a trait, then following description also seems to be not relevant.