On second thought, let's put this near the bottom of the file...

Author: Carlton Duffett

src/onelogin/saml2/xml_utils.py

@@ -31,27 +31,6 @@ class OneLogin_Saml2_XML(object):
     make_root = staticmethod(etree.Element)
     make_child = staticmethod(etree.SubElement)
 
-    @staticmethod
-    def cleanup_namespaces(tree_or_element, top_nsmap=None, keep_ns_prefixes=None):
-        """
-        Keeps the xmlns:xs namespace intact when etree.cleanup_namespaces is invoked.
-        :param tree_or_element: An XML tree or element
-        :type tree_or_element: etree.Element
-        :param top_nsmap: A mapping from namespace prefixes to namespace URIs
-        :type top_nsmap: dict
-        :param keep_ns_prefixes: List of prefixes that should not be removed as part of the cleanup
-        :type keep_ns_prefixes: list
-        :returns: An XML tree or element
-        :rtype: etree.Element
-        """
-        all_prefixes_to_keep = [
-            OneLogin_Saml2_Constants.NS_PREFIX_XS
-        ]
-
-        if keep_ns_prefixes:
-            all_prefixes_to_keep = list(set(all_prefixes_to_keep.extend(keep_ns_prefixes)))
-
-        return etree.cleanup_namespaces(tree_or_element, keep_ns_prefixes=all_prefixes_to_keep)
 
     @staticmethod
     def to_string(xml, **kwargs):
@@ -144,6 +123,28 @@ def query(dom, query, context=None):
         else:
             return context.xpath(query, namespaces=OneLogin_Saml2_Constants.NSMAP)
 
+    @staticmethod
+    def cleanup_namespaces(tree_or_element, top_nsmap=None, keep_ns_prefixes=None):
+        """
+        Keeps the xmlns:xs namespace intact when etree.cleanup_namespaces is invoked.
+        :param tree_or_element: An XML tree or element
+        :type tree_or_element: etree.Element
+        :param top_nsmap: A mapping from namespace prefixes to namespace URIs
+        :type top_nsmap: dict
+        :param keep_ns_prefixes: List of prefixes that should not be removed as part of the cleanup
+        :type keep_ns_prefixes: list
+        :returns: An XML tree or element
+        :rtype: etree.Element
+        """
+        all_prefixes_to_keep = [
+            OneLogin_Saml2_Constants.NS_PREFIX_XS
+        ]
+
+        if keep_ns_prefixes:
+            all_prefixes_to_keep = list(set(all_prefixes_to_keep.extend(keep_ns_prefixes)))
+
+        return etree.cleanup_namespaces(tree_or_element, keep_ns_prefixes=all_prefixes_to_keep)
+
     @staticmethod
     def extract_tag_text(xml, tagname):
         open_tag = compat.to_bytes("<%s" % tagname)