ERROR: ImportError: No module named '_ctypes
If using RHEL/Fedora:
yum install libffi-devel
Debian/Ubuntu:
sudo apt-get install libffi-dev
重新編譯Python
cd Python-3.7.3/
./configure --with-ssl
make
make install
最後安裝pip3
python3 -m ensurepip --default-pip
good lucky！