从 python 脚本中静默运行 `pip install`

Question

正如标题所示，我想使用另一个 python 脚本静默安装 package。

我可以静默安装 package，也可以从另一个脚本安装 package。 但我不能将两者结合起来。

我努力了：

from pip._internal import main as pipmain
pipmain(['install', 'prompt_toolkit==1.0.14 --quiet'])
# Installs, but I still receive: 
# WARNING: pip is being invoked by an old script wrapper.

我也试过：

import subprocess
import sys

def install(package):
    subprocess.check_call([sys.executable, "-m", "pip3", "install", package, "--quiet"])
install('prompt_toolkit==1.0.14')
# Which fails.
# `returned non-zero exit status 1`