setup.py 文件源码

def install_lxml():
        try:
            import cython  # noqa: F401
        except ImportError:
            cython_was_installed = False
            pip(['install', '-v', 'cython'])
        else:
            cython_was_installed = True

        pip(['install', '-v', 'https://github.com/funkyfuture/lxml/tarball/smart_xpath#egg=lxml'])

        if not cython_was_installed:
            pip(['uninstall', '--yes', '-v', 'cython'])