'Returns the set of users the bot has already followed in the past.'

def get_do_not_follow_list(self):

    dnf_list = []
    with open(self.BOT_CONFIG['ALREADY_FOLLOWED_FILE'], 'r') as in_file:
        for line in in_file:
            dnf_list.append(int(line))
    return set(dnf_list)
