new_contents: from lxml import etree, builder, html
  from io import StringIO, BytesIO
  import os
  
  
  class CPyLXmlParser:
      def __init__(self, xstr, encoding="utf-8"):
          self.encoding = encoding
          self.xstr = None
          if xstr is None:
              raise ValueError("Source content is none!")
          else:
              self.xstr = xstr
  
      def parse(self, is_xml=True):
          parser = etree.XMLParser()
          if is_xml is False:
              parser = etree.HTMLParser()
          return etree.parse(self.xstr, parser)
  
      def test(self):
          pass
  
      def get_element(self):
          return ""
  
subject: update code