Python: Performing XSLT recursively on a directory of XML files

I've been using https://github.com/ajryan/RptToXml to extract out xml information from Crystal Reports. I then rip through the created xml files with xlst to provide detail information on how the reports are created.  This little python 3.5+ script uses https://www.saxonica.com/download/download_page.xml and will create html files from a directory tree containing xml files.  

TODO: Write an xxl file to convert Crystal Reports to Jasper Reports.

import os
import subprocess
import glob
from pathlib import Path
root_dir = r"C:\crystalxml"
xslFile = r"C:\Saxon\pretty.xsl"

for filename in glob.iglob(root_dir + '/**/*.xml', recursive=True):

 my_parts = filename.split("\\")
 justname = my_parts[-1].split('.')[0]
 my_dir = os.path.dirname(filename)
 newname = fr'{my_dir}\{justname}.html'
 cmd = fr'java -cp C:\Saxon\saxon-he-10.1.jar net.sf.saxon.Transform -t -s:"{filename}" -xsl:{xslFile} -o:"{newname}"'
 subprocess.call(cmd)