diff --git a/dendropy/dataio/newickreader.py b/dendropy/dataio/newickreader.py
index 6dcf3c5cb..f978729b9 100644
--- a/dendropy/dataio/newickreader.py
+++ b/dendropy/dataio/newickreader.py
@@ -303,7 +303,8 @@ def tree_iter(self,
                     taxon_symbol_map_fn=taxon_symbol_mapper.require_taxon_for_symbol)
             yield tree
             if tree is None:
-                raise StopIteration
+                # raise StopIteration
+                return
 
     def _read(self,
             stream,
diff --git a/dendropy/datamodel/treemodel.py b/dendropy/datamodel/treemodel.py
index 0ecfe3150..73146f085 100644
--- a/dendropy/datamodel/treemodel.py
+++ b/dendropy/datamodel/treemodel.py
@@ -772,6 +772,9 @@ def __hash__(self):
     def __eq__(self, other):
         return self is other
 
+    def __lt__(self, other):
+        return id(self) < id(other)
+
     ###########################################################################
     ### Basic Structure