ubuntu16.04无法为python安装progreebar

Question

当我尝试为python3.5安装进度条时，我遇到了一个错误：

我用 sudo pip安装进度条

它显示：

Collecting progressbar

正在下载progressbar-2.3.tar.gz

Complete output from command python setup.py egg_info:
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/tmp/pip-build-ktnxhtii/progressbar/setup.py", line 5, in <module>
    import progressbar
  File "/tmp/pip-build-ktnxhtii/progressbar/progressbar/__init__.py", line 59, in <module>
    from progressbar.widgets import *
  File "/tmp/pip-build-ktnxhtii/progressbar/progressbar/widgets.py", line 121, in <module>
    class FileTransferSpeed(Widget):
  File "/usr/lib/python3.5/abc.py", line 133, in __new__
    cls = super().__new__(mcls, name, bases, namespace)
ValueError: 'format' in __slots__ conflicts with class variable

----------------------------------------

命令＆＃34; python setup.py egg_info＆＃34;在/ tmp / pip-build-ktnxhtii / progressbar /

中失败并显示错误代码1

我不知道如何处理这个问题。请提前给我一些建议。