Partial fix for #75 - fixes problem in libXML (#92)

Co-authored-by: Adam Bem <adam.bem@zoho.eu>
Reviewed-on: R11/release11-tools-web#92

Backend-libXML/Parser.py

@@ -58,10 +58,16 @@ def xpath(source: str, xpath: str) -> str:
         nsmap.pop(None)
     
     result = root.xpath(xpath, namespaces=nsmap)
-    result_string = ""
-    for e in result:
-        result_string += etree.tostring(e, pretty_print=True).decode() + "\n"
-    return result_string
+    
+    # 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 = ""
+        for e in result:
+            result_string += etree.tostring(e, pretty_print=True).decode() + "\n"
+        return result_string