TypeError: start() got an unexpected keyword argument 'maxval'

报错：

最小示例代码：

xxx@lthpc:~/dataset/tubcrowd$ python3
Python 3.5.2 (default, Nov 17 2016, 17:05:23)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import progressbar
>>> pb = progressbar.ProgressBar()>>> pb.start(max_value=1)
Traceback (most recent call last):File "<stdin>", line 1, in <module>
TypeError: start() got an unexpected keyword argument 'max_value'# 根据网上的修改成maxval，还是报错：
>>> pb.start(maxval=1)
Traceback (most recent call last):File "<stdin>", line 1, in <module>
TypeError: start() got an unexpected keyword argument 'maxval'>>> progressbar.__version__
'2.5'

原因：progressbar版本不对，比如我是用了progressbar 2.5，更进一步的原因还未细究。

解决：卸载原来的progressbar，重新安装progressbar 3.46.1即可。其他版本还未测试过。仅供参考。

最小示例：

xxx@lthpc:~/dataset/tubcrowd$ source crowdflow_env/bin/activate
(crowdflow_env) xxx@lthpc:~/dataset/tubcrowd$ python
Python 3.5.2 (default, Nov 17 2016, 17:05:23)
[GCC 5.4.0 20160609] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import progressbar
>>> pb = progressbar.ProgressBar()
>>> pb.start(max_value=10)
N/A% (0 of 10) |                        | Elapsed Time: 0:00:00 ETA:  --:--:--<progressbar.bar.ProgressBar object at 0x7f971f47cb38>
>>> progressbar.__version__
'3.46.1'

另：可以直接安装progressbar2解决：

$ pip install progressbar2