public static string ForResult(this IEnumerable<IBoundary> boundaries, decimal? result)
{
if (result.HasValue)
{
var match =
boundaries.Where(boundary => result.Value >= boundary.MinResult)
.OrderByDescending(boundary => boundary.MinResult)
.FirstOrDefault();
if (match != null)
{
return match.Grade;
}
}
return string.Empty;
}