Why this interface exists

[lpatiny]

The new eslint rules forbid to have the following pattern and it is not clear for me why this Interface exists:

spectrum-generator/src/Spectrum2DGenerator.ts

Lines 105 to 118 in 6e673e9

	export interface Spectrum2DGenerator {
	addPeaks(peaks: Peak2D[] | Peak2DSeries, options?: AddPeak2DOptions): void;
	addPeak(peak: Peak2D, options?: AddPeak2DOptions): void;
	getSpectrum(options?: GetSpectrum2DOptions | boolean): void;
	reset(): void;
	}
	export class Spectrum2DGenerator implements Spectrum2DGenerator {
	private from: XYNumber;
	private to: XYNumber;
	private nbPoints: XYNumber;
	public interval: XYNumber;
	private data: Data2D;
	private maxPeakHeight: number;

@jobo322 Could you check and fix this issue ?