Python问题：ImportError: cannot import name 'gen' from 'tornado' (unknown location)

背景：

使用kali安装子域名收集工具（oneforall）时，安装文档的步骤执行很顺利，但在执行主程序时遇到的如下报错。

RHEL/Centos系统
1、安装git和pip3
sudo yum update
sudo yum install git python3-pip -y

2、克隆OneForAll项目
git clone https://gitee.com/shmilylty/OneForAll.git

3、安装相关依赖
cd OneForAll/
sudo yum install gcc python3-devel python3-pip -y
sudo python3 -m pip install -U pip setuptools wheel -i https://mirrors.aliyun.com/pypi/simple/
sudo pip3 install uvloop -i https://mirrors.aliyun.com/pypi/simple/
sudo pip3 install --ignore-installed -r requirements.txt -i https://mirrors.aliyun.com/pypi/simple/
python3 oneforall.py --help

问题描述：

root@unic0rn:~/web/OneForAll# python3 oneforall.py --help
Traceback (most recent call last):
  File "oneforall.py", line 15, in <module>
    import dbexport
  File "/root/web/OneForAll/dbexport.py", line 13, in <module>
    from common import utils
  File "/root/web/OneForAll/common/utils.py", line 13, in <module>
    import tenacity
  File "/usr/local/lib/python3.8/dist-packages/tenacity/__init__.py", line 504, in <module>
    from tenacity.tornadoweb import TornadoRetrying
  File "/usr/local/lib/python3.8/dist-packages/tenacity/tornadoweb.py", line 23, in <module>
    from tornado import gen
ImportError: cannot import name 'gen' from 'tornado' (unknown location)

解决方法：

安装较低版本的tornado ，命令如下：

pip install tornado==5.1.1

然后就可以正常使用了

python3 oneforall.py --target example.com run
python3 oneforall.py --targets ./example.txt run