Couple of patches for Travis

lib/core/compat.py

@@ -6,6 +6,7 @@ See the file 'LICENSE' for copying permission
 """
 
 import binascii
+import functools
 import math
 import os
 import random
@@ -201,6 +202,31 @@ def round(x, d=0):
     else:
         return float(math.ceil((x * p) - 0.5))/p
 
+def cmp_to_key(mycmp):
+    """Convert a cmp= function into a key= function"""
+    class K(object):
+        __slots__ = ['obj']
+        def __init__(self, obj, *args):
+            self.obj = obj
+        def __lt__(self, other):
+            return mycmp(self.obj, other.obj) < 0
+        def __gt__(self, other):
+            return mycmp(self.obj, other.obj) > 0
+        def __eq__(self, other):
+            return mycmp(self.obj, other.obj) == 0
+        def __le__(self, other):
+            return mycmp(self.obj, other.obj) <= 0
+        def __ge__(self, other):
+            return mycmp(self.obj, other.obj) >= 0
+        def __ne__(self, other):
+            return mycmp(self.obj, other.obj) != 0
+        def __hash__(self):
+            raise TypeError('hash not implemented')
+    return K
+
+# Note: patch for Python 2.6
+if not hasattr(functools, "cmp_to_key"):
+    functools.cmp_to_key = cmp_to_key
 
 if sys.version_info >= (3, 0):
     xrange = range