Process an element in a Dictionary only if it exists

DictionaryExtension.cs

namespace System.Collections.Generic
{
    public static class DictionaryExtension
    {
        public static void ProcessValue<TKey, TValue>(this IDictionary<TKey, TValue> x, TKey key, Action<TValue> action)
        {
            TValue o;
            if (x.TryGetValue(key, out o))
                action(o);
        }
    }
}