2.4 defines groupby, so there's no need to define our own.

src/utils/iter.py

@@ -27,6 +27,7 @@
 # POSSIBILITY OF SUCH DAMAGE.
 ###
 
+import sys
 import new
 import random
 
@@ -48,6 +49,7 @@ def trueCycle(iterable):
         if not yielded:
             raise StopIteration
 
+if sys.version_info < (2, 4, 0):
     def groupby(key, iterable):
         if key is None:
             key = lambda x: x