Added comments and returned back to previous solution

Backend-libXML/Parser.py

@@ -56,7 +56,10 @@ def xpath(source: str, xpath: str) -> str:
         nsmap.pop(None)
     
     result = root.xpath(xpath, namespaces=nsmap)
-    if isinstance(result, etree._ElementUnicodeResult):
+    
+    # root.xpath can return 4 types: float, string, bool and list.
+    # List is the only one that can't be simply converted to str
+    if result is not list:
         return str(result)
     else:
         result_string = ""