Add buttons

        :param args:
        :return: self
        :rtype: :obj:`types.InlineKeyboardMarkup`

def add(self, *args):
        """
        Add buttons

        :param args:
        :return: self
        :rtype: :obj:`types.InlineKeyboardMarkup`
        """
        row = []
        for index, button in enumerate(args, start=1):
            row.append(button)
            if index % self.row_width == 0:
                self.inline_keyboard.append(row)
                row = []
        if len(row) > 0:
            self.inline_keyboard.append(row)
        return self