Telebot library, inline button has no reaction, how to solve?

Question

Python

markup_inline = types.InlineKeyboardMarkup(row_width=1)
        item_cours5 = types.InlineKeyboardButton(text = cours5, callback_data='1')
        item_cours6 = types.InlineKeyboardButton(text = cours6, callback_data='2')
        item_cours7 = types.InlineKeyboardButton(text = cours7, callback_data='3')
        item_cours8 = types.InlineKeyboardButton(text = cours8, callback_data='4')
        item_cours9 = types.InlineKeyboardButton(text = cours9, callback_data='5')
        markup_inline.add(item_cours5, item_cours6, item_cours7, item_cours8, item_cours9)

I connected the keyboard, everything works fine, it appears under the desired message

@bot.callback_query_handler(func = lambda message: True)
def answer(message):
        if message.data == '1':
            bot.send_message(message.chat.id, "Открываю...")

Here is the inline button handler, as soon as it did not twist, there was no reaction ...

Answer 1

no reaction

But what about the error?

AttributeError: 'CallbackQuery' object has no attribute 'chat'

See examples of Inline keyboard https://github.com/eternnoir/pyTelegramBotAPI/blob...
Do it print(message)in the function answer, you will see that there is no such field as chat

Answer 2

Try this:
keyboard = types.InlineKeyboardMarkup()
rele1 = types.InlineKeyboardButton(text="cours5", callback_data="1")
rele2 = types.InlineKeyboardButton(text="cours6", callback_data="2")
backbutton = types. InlineKeyboardButton(text="Back", callback_data="mainmenu")
keyboard.add(rele1)
keyboard.add(rele2)
keyboard.add(backbutton)
or try removing the quotes in cours