def get_user_info(update):
    """Return user information who interacts with bot."""
    return 'Request from user_id: {0}, username: {1},' \
           'first_name: {2}, last_name: {3}'.format(
        update.message.chat.id,
        update.message.chat.username,
        update.message.chat.first_name,
        update.message.chat.last_name)