Fix: convert empty attribute values received from html.parser into empty-string values that xml.etree.ElementPath can use during attribute search

Author: jayaddison

htmlement.py

@@ -330,7 +330,7 @@ def _handle_starttag(self, tag, attrs, self_closing=False):
         # Add tag element to tree if we have no filter or that the filter matches
         if enabled or self._search(tag, attrs):
             # Convert attrs to dictionary
-            attrs = dict(attrs) if attrs else {}
+            attrs = {k: v or str() for k, v in attrs}
             self._flush()
 
             # Create the new element