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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 get_saml_slos(cls, logout_request):
 """returns saml logout ticket info"""

        try:
            root = etree.fromstring(logout_request)
            return root.xpath(
                "//samlp:SessionIndex",
                namespaces={'samlp': "urn:oasis:names:tc:SAML:2.0:protocol"})
        except etree.XMLSyntaxError:
            return None