fix libxml xpath bugs

Backend-libXML/Parser.py

@@ -1,3 +1,5 @@
+from typing import Any
+
 from lxml import etree, html
 from io import BytesIO
 
@@ -79,9 +81,11 @@ def xpath(source: str, xpath: str) -> str:
     else:
         result_string = ""
         for e in result:
-            result_string += etree.tostring(e, pretty_print=True).decode() + "\n"
-        return result_string, "node"
-
+            if isinstance(e, etree._Element):
+                result_string += etree.tostring(e, pretty_print=True).decode() + "\n"
+            else:
+                result_string += str(e) + "\n"
+    return result_string, "node"
 
 
 def xsd(source: str, xsd: str) -> bool: