declare namespace Ext {
    export namespace mixin {
        export interface ResponsiveConfig {
            responsiveConfig?: object;
            responsiveFormulas?: object;
        }

        export class Responsive extends Ext.Mixin  {
            public getResponsiveConfig(): void;
            public getResponsiveFormulas(): void;
            public setResponsiveConfig(): void;
            public setResponsiveFormulas(): void;
        }
    }
}