req.py 文件源码

def add(self, path):
        path = normalize_path(path)
        if not os.path.exists(path):
            return
        if self._permitted(path):
            self.paths.add(path)
        else:
            self._refuse.add(path)

        # __pycache__ files can show up after 'installed-files.txt' is created, due to imports
        if os.path.splitext(path)[1] == '.py' and uses_pycache:
            self.add(imp.cache_from_source(path))