change xml class

ml/tools.py

@@ -199,9 +199,12 @@ def find_nodes(self, path):
         new_path = ""
         for _path in path_list:
             if ":" not in _path:
-                _path = "standford_ns:{}".format(_path)
+                _path = "{" + self._namespace.get('') + "}" + _path
             new_path += _path
             new_path += "/"
         if new_path[-1] == "/":
             new_path = new_path[:-1]
-        return self.root.find(new_path, self._namespace)
+        return self.root.findall(new_path, self._namespace)
+
+    def to_string(self, root):
+        return self.et.tostring(root, "unicode", "xml")
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