Bypassing URL verification

I’m dealing with a URL validation function that was made by the developer (instead of using trusted methods).

Here is a slightly modified version of the function:

    public static bool IsValidURL(string url) {         string parsedurl = url.ToLower().Substring(8, url.IndexOf("/", 8) - 8);         return url.StartsWith("https") && parsedurl.EndsWith("");     } 

I need this function to return true for a URL string I supply and the URL must also be compatible with C#’s WebClient. My goal is to have it to connect to my own web server, any ideas?