public static By AsContainer(this By containerBy, By childBy)
{
string childCss = childBy.ToString();
if (!childCss.Contains("Css"))
{
throw new ArgumentException($"{childCss} is not a CSS Selector.");
}
childCss = childCss.Substring(childCss.IndexOf(':') + 1).TrimStart();
return(containerBy.AsContainer(childCss));
}
