declare module 'markdown-it-anchor' {
  import MarkdownIt from 'markdown-it';

  interface AnchorOptions {
    level?: number | number[];
    slugify?: (s: string) => string;
    permalink?: boolean | ((slug: string, opts: AnchorOptions, state: any, idx: number) => void);
    [key: string]: any;
  }

  function markdownItAnchor(md: MarkdownIt, opts?: AnchorOptions): void;
  export default markdownItAnchor;
}