FIX: Better None handling.

src/caoscrawler/crawl.py

@@ -183,6 +183,11 @@ def _treat_merge_error_of(newrecord, record):
     """
     for this_p in newrecord.properties:
         that_p = record.get_property(this_p.name)
+        if that_p is None:
+            logger.debug(f"Property {this_p.name} does not exist in the second entity. Note that "
+                         "this should not be the reason for the merge conflict.")
+            continue
+
         if (isinstance(this_p.value, db.Entity)
                 and isinstance(that_p.value, db.Entity)):
             if this_p.value.id is not None and that_p.value.id is not None: