初探Scrapy 時，也不知道按照哪里的文檔裝的，由於安裝低版本的pyasn1 后，使用pip uninstall 都 卸不了
步驟如下：
異常：
pyasn1-modules 0.2.1 has requirement pyasn1<0.5.0,>=0.4.1, but you'll have pyasn1 0.1.7 which is incompatible.
網上方案：
https://blog.csdn.net/ksx_120999/article/details/80012650
pip install pyasn1-modules
報錯
Cannot uninstall 'pyasn1'. It is a distutils installed project and thus we cannot accurately determine which files belong to it which would lead to only a partial uninstall.
貌似重新安裝是先uninstall 然后，卸不了
於是從 pyasn1 官網下源代碼再安裝
https://pypi.org/project/pyasn1/#files 官網地址
下載
下載后，解壓，進入根目錄
python setup.py build
python setup.py install
OK，pyasn1 己安裝指定版本。