declare namespace Ext {
    export namespace chart {
        export namespace axis {
            export namespace layout {
                export interface CombineDuplicateConfig {
                    axis?: Ext.chart.axis.Axis;
                    listeners?: object;
                }

                export class CombineDuplicate extends Ext.chart.axis.layout.Discrete  {
                }
            }
        }
    }
}