Extension methods for generic Dictionary

DictionaryHelpers.cs

using System.Collections.Generic;

namespace KMorcinek.Common
{
    public static class DictionaryExtensions
    {
        public static void IncrementAt<T>(this Dictionary<T, int> dictionary, T index)
        {
            int count = 0;

            dictionary.TryGetValue(index, out count);

            dictionary[index] = ++count;
        }
    }
}

var newDic = oldDic.ToDictionary(x => x.Value, x => x.Key);