code: def create_from_xmlfile(cls, xmlfile, extdir=None):
          
          root = ElementTree.ElementTree(file=xmlfile).getroot()
          srcs = root.findall('source')
          if len(srcs) == 0:
              raise Exception('No sources found.')
          return cls.create_from_xml(srcs[0], extdir=extdir)
docs: Create a Source object from an XML file.
  
          Parameters
          ----------
          xmlfile : str
              Path to XML file.
  
          extdir : str
              Path to the extended source archive.