Error when using microsoft-web-helpers package in .net core App

I am trying to use Bing maps in my asp core app framework 3.1. i installed microsoft-web-helpers 2.1.207. when building this error appears:

TypeLoadException: Could not load type 'System.Web.IHtmlString' from assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'

here is my my code

    @Maps.GetBingHtml(key: "THE-KEY",
    latitude: "33.5138° N",
    longitude: "36.2765° E",
    width: "300",
    height: "300"
 )