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.