Index: Lib/pprint.py
===================================================================
--- Lib/pprint.py	(revision 76934)
+++ Lib/pprint.py	(working copy)
@@ -70,6 +70,38 @@
     """Determine if object requires a recursive representation."""
     return _safe_repr(object, {}, None, 0)[2]
 
+class _safe_key:
+    """Helper function for key functions when sorting unorderable objects.
+
+    The wrapped-object will fallback to an Py2.x style comparison for
+    unorderable types (sorting first comparing the type name and then by
+    the obj ids).  Does not work recursively, so dict.items() must have
+    _safe_key applied to both the key and the value.
+
+    """
+
+    __slots__ = ['obj']
+
+    def __init__(self, obj):
+        self.obj = obj
+
+    def __lt__(self, other):
+        try:
+            if hasattr(self.obj, '__lt__'):
+                rv = self.obj.__lt__(other.obj)
+            else:
+                rv = self.obj.__cmp__(other.obj) < 0
+        except TypeError:
+            rv = NotImplemented
+        if rv is NotImplemented:
+            rv = (str(type(self.obj)), id(self.obj)) < \
+                 (str(type(other.obj)), id(other.obj))
+        return rv
+
+def _safe_tuple(t):
+    "Helper function for comparing 2-tuples"
+    return _safe_key(t[0]), _safe_key(t[1])
+
 class PrettyPrinter:
     def __init__(self, indent=1, width=80, depth=None, stream=None):
         """Handle pretty printing operations onto a stream using a set of
@@ -144,8 +176,7 @@
             if length:
                 context[objid] = 1
                 indent = indent + self._indent_per_level
-                items  = object.items()
-                items.sort()
+                items  = sorted(object.items(), key=_safe_tuple)
                 key, ent = items[0]
                 rep = self._repr(key, context, level)
                 write(rep)
@@ -181,7 +212,7 @@
                     return
                 write('set([')
                 endchar = '])'
-                object = sorted(object)
+                object = sorted(object, key=_safe_key)
                 indent += 4
             elif issubclass(typ, frozenset):
                 if not length:
@@ -189,7 +220,7 @@
                     return
                 write('frozenset([')
                 endchar = '])'
-                object = sorted(object)
+                object = sorted(object, key=_safe_key)
                 indent += 10
             else:
                 write('(')
@@ -274,7 +305,8 @@
         append = components.append
         level += 1
         saferepr = _safe_repr
-        for k, v in sorted(object.items()):
+        items = sorted(object.items(), key=_safe_tuple)
+        for k, v in items:
             krepr, kreadable, krecur = saferepr(k, context, maxlevels, level)
             vrepr, vreadable, vrecur = saferepr(v, context, maxlevels, level)
             append("%s: %s" % (krepr, vrepr))