Insert new interface method namespace Typescript

Question

I am working with a third-party library that has a namespace thisLibrary and within that namespace has an interface Options. I would like to add a property to the Options interface and then use the update version of Options within my code. The index.d.ts file for the library looks like this:

export = thisLibrary;
export as namespace thisLibrary;

declare function thisLibrary(elements: HTMLElement | HTMLElement[], options: thisLibrary.Options): void;

declare namespace thisLibrary {
   const propA: boolean;
   let propB: number;

   interface Options{
      list?: ListEntry[] | any[];
      propC?: string;
      propD?: string | number;
   }
}

I would like to be able to import thisLibrary into my code and then add typing for propE?: boolean such that I can pass propE into my function call for thisLibrary and not raise errors.

I'm working within an Angular framework, and my code looks like this:

import * as thisLibrary from 'thisLibrary';

export class MyComponent implements OnInit {
   constructor() {}

   ngOnInit(): void {
      this.doThis()
   }

   private doThis(): void { 
      const myHTML = this.getHTML()
      thisLibrary(myHTML, {
         list: [[a, 10], [b, 7]],
         propC: 'blah blah',
         propD: 10,
         propE: true
      }
   }

At the moment, this code throws an error in my TS linter because propE "does not exist in type Options".