def setUp(self):
        """
        Create a root directory and instantiate a shell.
        """
        self.root = filepath.FilePath(self.mktemp())
        self.root.createDirectory()
        self.shell = ftp.FTPShell(self.root)

        Create a root directory and instantiate a shell.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py