Issues #10017 and #14998: Fix TypeError using pprint on dictionaries with unorderable key.
diff --git a/Lib/pprint.py b/Lib/pprint.py
index b8417f5..ae96dde 100644
--- a/Lib/pprint.py
+++ b/Lib/pprint.py
@@ -86,7 +86,11 @@
         self.obj = obj
 
     def __lt__(self, other):
-        rv = self.obj.__lt__(other.obj)
+        try:
+            rv = self.obj.__lt__(other.obj)
+        except TypeError:
+            rv = NotImplemented
+
         if rv is NotImplemented:
             rv = (str(type(self.obj)), id(self.obj)) < \
                  (str(type(other.obj)), id(other.obj))