Todoistbot-main-function.py

class TodoistBot:
# all other functions
# .
# .
# .

    # handler for buttons
    def button(self, bot, update):
        query = update.callback_query
    
    # general handler for messages
    def general_handler(self, bot, update):
        chat_id = update.message.chat_id
        text = update.message.text

    def main(self):
        updater = self.updater
        dp = updater.dispatcher

        # Add command handlers
        dp.add_handler(CommandHandler('projects', self.projects))
        # other commands will goes here

        # Add callback handlers for buttons
        updater.dispatcher.add_handler(CallbackQueryHandler(self.button))

        # general message handler
        updater.dispatcher.add_handler(MessageHandler(Filters.all, self.general_handler))

        updater.start_polling()
        updater.idle()