python使用pygal报错：

ValueError: Invalid PI name 'b'xml'' 相关代码：hist.render_to_file('1.svg') 详细错误：

I have try to solve it by install new version of lxml,but can't work
just like this
blog.csdn.net/shuxue051/article/details/47686761

I hope somenoe can help me to solve it,Thank you!