Warning message: Result of call to 'URL' is unused

[umoruj]

The library works perfectly, as I only get a warning message saying
Result of call to 'URL' is unused
for the function shown below:

open func URL(string urlString: String) -> Self {
URL(Foundation.URL(string: urlString))
return self
}

And also any place where I make the call to popup the webview giving it the specified URL.

xcode version: Version 8.3.2 (8E2002)

Thanks
Joseph