public static void ReadFromCsv <TKey>(this IStatistic <TKey> stat, TextReader reader, Func <string, TKey> keyParser)
{
stat.Clear();
while (reader.Peek() != -1)
{
var ss = reader.ReadLine().Split(',');
var key = keyParser(ss[0]);
var freq = int.Parse(ss[1]);
stat.Add(key, freq);
}
}
