private static void Add(Dictionary <string, List <ColumnInfo> > map, ColumnRole role, ColumnInfo info) { Contracts.AssertValue(map); Contracts.AssertNonEmpty(role.Value); Contracts.AssertValue(info); if (!map.TryGetValue(role.Value, out var list)) { list = new List <ColumnInfo>(); map.Add(role.Value, list); } list.Add(info); }