Mixin support?

1. Mixining two classes that both inherit from pyrsistent.PClass fails:

import pyrsistent

class TimestampMixin(pyrsistent.PClass):
    created_at = pyrsistent.field()
    deleted_at = pyrsistent.field()
    updated_at = pyrsistent.field()

class IDMixin(pyrsistent.PClass):
    id = pyrsistent.field()

class UserEntity(IDMixin, TimestampMixin):
    pass

produces:

---------------------------------------------------------------------------
TypeError                                 Traceback (most recent call last)
<ipython-input-1-808a9f22c5af> in <module>()
      9     id = pyrsistent.field()
     10
---> 11 class UserEntity(IDMixin, TimestampMixin):
     12     pass

~/.local/share/virtualenvs/server-hvEypR1j/lib/python3.6/site-packages/pyrsistent/_pclass.py in __new__(mcs, name, bases, dct)
     20             dct['__slots__'] += ('__weakref__',)
     21
---> 22         return super(PClassMeta, mcs).__new__(mcs, name, bases, dct)
     23
     24 _MISSING_VALUE = object()

TypeError: multiple bases have instance lay-out conflict

2. Using a mixin which doesn't inherit from PClass doesn't have it's fields registered:

import pyrsistent

class TimestampMixin:
    created_at = pyrsistent.field()
    deleted_at = pyrsistent.field()
    updated_at = pyrsistent.field()

class IDMixin(pyrsistent.PClass):
    id = pyrsistent.field()

class UserEntity(IDMixin, TimestampMixin):
    pass

assert list(UserEntity._pclass_fields) == ['id']  # expecting: id, created_at, deleted_at, updated_at

Is there a suggested way to use mixins without falling back to: type('UserEntity', (pyrsistent.PClass,), namespace) where namespace is effectively a user-manifest mixin?