1 files changed, 19 insertions, 2 deletions
diff --git a/layman/compatibility.py b/layman/compatibility.py
index b71a8af..e6206db 100644
--- a/layman/compatibility.py
+++ b/layman/compatibility.py
@@ -6,8 +6,6 @@
  Distributed under the terms of the GNU General Public License v2
 """
 
-import sys, types
-
 
 def encode(text, enc="UTF-8"):
     """py2, py3 compatibility function"""
@@ -27,3 +25,22 @@ def fileopen(path, mode='r', enc="UTF-8"):
         f = open(path, mode)
     return f
 
+
+def cmp_to_key(mycmp):
+    'Convert a cmp= function into a key= function'
+    class K(object):
+        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
+    return K