ampersand-filtered-subcollection.js
function (query, indexName) {
        var model = this.collection.get(query, indexName);
        if (model && includes(this.models, model)) return model;
    }
function (query, indexName) {
        var model = this.collection.get(query, indexName);
        if (model && includes(this.models, model)) return model;
    }
function ( query , indexName ) { var model = this . collection . get ( query , indexName ) ; if ( model && includes ( this . models , model ) ) return model ; }
proxy `get` method to the underlying collection
proxy get method to the underlying collection