declare namespace Ext {
    export namespace util {
        export interface MixedCollectionConfig {
            allowFunctions?: boolean;
            defaultSortDirection?: string;
            listeners?: object;
            multiSortLimit?: number;
            sorters?: Ext.util.Sorter[] | object[];
            sortRoot?: string;
        }

        export class MixedCollection extends Ext.util.AbstractMixedCollection  {
            public constructor(config?: object);
            public findInsertionIndex(newItem?: object, sorterFn?: CallableFunction): number;
            public sortBy(sorterFn?: CallableFunction): void;
            public sortByKey(direction?: string, fn?: CallableFunction): void;
        }
    }
}