private void AddLetterKeyboardRow(string line, Language lang)
        {
            var row = new KeyboardRow();

            foreach (char ch in line)
            {
                var letter = new LetterKeyboardButton()
                {
                    Title = ch.ToString(),
                    Language = lang
                };

                letters.Add(letter);
                row.Buttons.Add(letter);
            }

            Rows.Add(row);
        }
        private void AddKeyboardRow(string line)
        {
            var row = new KeyboardRow();

            foreach (var ch in line)
            {
                row.Buttons.Add(new KeyboardButton() { Title = ch.ToString() });
            }

            Rows.Add(row);
        }