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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def _unescape_math(xml):
 """Unescapes Math from Mathjax to MathML."""

    xpath_math_script = etree.XPath(
            '//x:script[@type="math/mml"]',
            namespaces={'x': 'http://www.w3.org/1999/xhtml'})
    math_script_list = xpath_math_script(xml)
    for mathscript in math_script_list:
        math = mathscript.text
        # some browsers double escape like e.g. Firefox
        math = unescape(unescape(math))
        mathscript.clear()
        mathscript.set('type', 'math/mml')
        new_math = etree.fromstring(math)
        mathscript.append(new_math)
    return xml