This patch fixes two test failures.  It was downloaded from:
https://github.com/jeetsukumaran/DendroPy/commit/93f984bba7a6c588a28ca87f4e557ce283809453

From 93f984bba7a6c588a28ca87f4e557ce283809453 Mon Sep 17 00:00:00 2001
From: jeetsukumaran <jeetsukumaran@gmail.com>
Date: Tue, 21 Feb 2017 16:41:01 -0500
Subject: [PATCH] Update to Python 3 container and iteration semantics

---
 dendropy/dataio/newickreader.py | 3 ++-
 dendropy/datamodel/treemodel.py | 3 +++
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/dendropy/dataio/newickreader.py b/dendropy/dataio/newickreader.py
index 6dcf3c5..f978729 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 0ecfe31..73146f0 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
 
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<tr><td><span title='2019-10-27 00:49:25 +0200'>2019-10-27</span></td><td><a href='/guix/commit/gnu/packages/gettext.scm?id=229818064a154a38dff1c0a9a6bc3ba66a2d4925'>gnu: po4a: Update to 0.57.</a><span class='msg-avail'>...</span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2019-07-02 01:06:31 +0200'>2019-07-02</span></td><td><a href='/guix/commit/gnu/packages/gettext.scm?id=3730e3c64e2bc9b444281a17282aa7406e20d093'>gnu: gettext: Update to 0.20.1.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2019-06-08 23:49:46 +0200'>2019-06-08</span></td><td><a href='/guix/commit/gnu/packages/gettext.scm?id=04aec35b783a0ec68fd09d8de6d0b3562e99047d'>gnu: po4a: Update to 0.56.</a><span class='msg-avail'>...</span></td><td>Marius Bakke</td></tr>
<tr><td><span title='2019-05-22 00:09:42 +0200'>2019-05-22</span></td><td><a href='/guix/commit/gnu/packages/gettext.scm?id=ea54133367aad77a9e941fba18fe57ab3e1ab5d9'>gnu: Add libtextstyle.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-22 00:09:42 +0200'>2019-05-22</span></td><td><a href='/guix/commit/gnu/packages/gettext.scm?id=69cb225c97f2099da9188e70fa9f3252d088044d'>gnu: gettext-minimal: Specify upstream name and CPE name.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>