declare namespace Ext {
    export namespace chart {
        export namespace axis {
            export namespace segmenter {
                export interface NumericConfig {
                    axis?: Ext.chart.axis.Axis;
                }

                export class Numeric extends Ext.chart.axis.segmenter.Segmenter  {
                    public exactStep(min?: any, estStepSize?: any): object;
                }
            }
        }
    }
}