/// <summary>
/// Computes the sum of a sequence of <see cref="ItemAttributes"/> values.
/// </summary>
/// <param name="itemAttributes">A sequence of <see cref="ItemAttributes"/> values to calculate the sum of.</param>
/// <returns></returns>
public static ItemAttributes Sum(this IEnumerable <ItemAttributes> itemAttributes)
{
var target = new ItemAttributes();
foreach (var attr in itemAttributes.Where(a => a != null))
{
ItemAttributes.SumIntoLeftOperand(target, attr);
}
return(target);
}