BotGenerator/Generator/StringToolsExtensions.cs

using System.Collections.Generic;

namespace Generator
{
    public static class StringToolsExtensions
    {
        /// <summary>
        /// Add a string to a list only if it doesnt already exist
        /// </summary>
        public static void AddUnique(this IList<string> self, string item)
        {
            if (!self.Contains(item))
                self.Add(item);
        }
    }
}