Using model constant in mixin in emberjs

I have a class

import DS from 'ember-data';

export default DS.Model.extend({
    name: DS.attr('string'),
    label: DS.attr('string'),
    cast: DS.attr('string'),
    isExpression: DS.attr('boolean'),
    isSecondary: DS.attr('boolean'),
    initialValue: DS.attr('string'),
    value: DS.attr('string'),
    units: DS.attr('string'),
    month: DS.attr('date'),
    inProgress: DS.attr('boolean'),
});

paymentAttribute.reopenClass({
    knownCasts: [ 'integer', 'boolean', 'float', 'string', 'expression' ]
});

and I want in configuration mixin use knownCasts like

options : {
    items: paymentAttribute.knownCasts
}

but i get error of paymentAttribute is not defined as expected. How should I import class to get that constant?