Exported SVG sankey is invalid

[BenPortner]

Sankey diagrams exported in SVG format cannot be opened in the browser. The latest version of Firefox gives this error:

XML Parsing Error: duplicate attribute
Location: file:///C:/Users/.../svg_export.svg
Line Number 1, Column 43:

Upon checking the file content, I realized that the default namespace attribute is declared twice, causing the parser to crash:

<svg xmlns="http://www.w3.org/1999/xhtml" xmlns="http://www.w3.org/2000/svg" ...

I wrote a quick python module which looks through a directory and fixes all svg files with the above error:

import glob

path = r"C:\path\to\*.svg"
files = glob.glob(path)

for file in files:
    with open(file, "r") as f:
        text = f.read()
        text = text.replace('xmlns="http://www.w3.org/1999/xhtml"','xmlns:xhtml="http://www.w3.org/1999/xhtml"')
    with open(file, "w") as f:
        f.write(text)

[marc-vdm]

@BenPortner Thanks for both reporting and contributing to the issue! Really great that you've taken the time to look at this.

@nabilahmed739 I've added you as reviewer as you know more about this. Would you have time? Otherwise please let me know!