code: def _write_xml(xmlfile, srcs):
          
          root = ElementTree.Element('source_library')
          root.set('title', 'source_library')
  
          for src in srcs:
              src.write_xml(root)
  
          output_file = open(xmlfile, 'w')
          output_file.write(utils.prettify_xml(root))
docs: Save the ROI model as an XML