Python 2.7 忽略xhtml名称空间下带有xmldiff的样式化标记

我使用xmldiff来显示两个xhtml文件中的差异。有一种方法可以根据忽略结果文件中的样式标记

有人知道我如何识别xhtml:b作为样式标签吗？ 这些是我的文件：

<xml xmlns:xhtml="http://www.w3.org/1999/xhtml">
    <xhtml:div>one two three four</xhtml:div>
</xml>

到

但我只得到了这个错误：

Traceback (most recent call last):
  File "c:/Users/paolo/Documents/12_raw_handle/test.py", line 89, in <module>
    formatter=formatter_xhtml)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 45, in diff_texts
    diff_options=diff_options, formatter=formatter)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 39, in _diff
    formatter=formatter)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 21, in diff_trees
    formatter.prepare(left, right)
  File "C:\Python27\lib\site-packages\xmldiff\formatting.py", line 322, in prepare
    self.placeholderer.do_tree(left_tree)
  File "C:\Python27\lib\site-packages\xmldiff\formatting.py", line 162, in do_tree
    for elem in tree.xpath('//'+'|//'.join(self.text_tags)):
  File "src\lxml\etree.pyx", line 1582, in lxml.etree._Element.xpath
  File "src\lxml\xpath.pxi", line 305, in lxml.etree.XPathElementEvaluator.__call__
  File "src\lxml\xpath.pxi", line 225, in lxml.etree._XPathEvaluatorBase._handle_result
lxml.etree.XPathEvalError: Undefined namespace prefix

回溯（最近一次呼叫最后一次）：
文件“c:/Users/paolo/Documents/12_raw_handle/test.py”，第89行，in
格式化程序=格式化程序（xhtml）
文件“C:\Python27\lib\site packages\xmldiff\main.py”，第45行，不同文本
差异选项=差异选项，格式化程序=格式化程序）
文件“C:\Python27\lib\site packages\xmldiff\main.py”，第39行，in_diff
格式化程序=格式化程序）
文件“C:\Python27\lib\site packages\xmldiff\main.py”，第21行，在diff_树中
格式化程序。准备（左、右）
文件“C:\Python27\lib\site packages\xmldiff\formatting.py”，第322行，在prepare中
self.placeholder.do_树（左_树）
文件“C:\Python27\lib\site packages\xmldiff\formatting.py”，第162行，在do_树中
对于tree.xpath（'/'+'|/'.join（self.text_标记））中的元素：
lxml.etree.\u Element.xpath中的文件“src\lxml\etree.pyx”，第1582行
文件“src\lxml\xpath.pxi”，第305行，在lxml.etree.XPathElementEvaluator__
文件“src\lxml\xpath.pxi”，第225行，在lxml.etree.\u xpatheevaluorbase.\u handle\u result中
lxml.etree.xpathevaleror:未定义的命名空间前缀

formatter = HTMLFormatter(
    text_tags=('p', 'h1', 'h2', 'h3', 'h4', 'h5', 'h6', 'li', 'div'),
    formatting_tags=('b', 'u', 'i', 'strike', 'em', 'super',
    'sup', 'sub', 'link', 'a', 'span')
    )

formatter_xhtml = HTMLFormatter(
    text_tags=('xhtml:p', 'xhtml:h1', 'xhtml:h2', 'xhtml:h3', 'xhtml:h4', 'xhtml:h5', 'xhtml:h6', 'xhtml:li', 'xhtml:div'),
    formatting_tags=('xhtml:b', 'xhtml:u', 'xhtml:i', 'xhtml:strike', 'xhtml:em', 'xhtml:super',
    'xhtml:sup', 'xhtml:sub', 'xhtml:link', 'xhtml:a', 'xhtml:span')
    )

Traceback (most recent call last):
  File "c:/Users/paolo/Documents/12_raw_handle/test.py", line 89, in <module>
    formatter=formatter_xhtml)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 45, in diff_texts
    diff_options=diff_options, formatter=formatter)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 39, in _diff
    formatter=formatter)
  File "C:\Python27\lib\site-packages\xmldiff\main.py", line 21, in diff_trees
    formatter.prepare(left, right)
  File "C:\Python27\lib\site-packages\xmldiff\formatting.py", line 322, in prepare
    self.placeholderer.do_tree(left_tree)
  File "C:\Python27\lib\site-packages\xmldiff\formatting.py", line 162, in do_tree
    for elem in tree.xpath('//'+'|//'.join(self.text_tags)):
  File "src\lxml\etree.pyx", line 1582, in lxml.etree._Element.xpath
  File "src\lxml\xpath.pxi", line 305, in lxml.etree.XPathElementEvaluator.__call__
  File "src\lxml\xpath.pxi", line 225, in lxml.etree._XPathEvaluatorBase._handle_result
lxml.etree.XPathEvalError: Undefined namespace prefix