we depend on python 2.6, use itertools.combinations instead of our own implementation

mboximport.py

@@ -8,6 +8,7 @@ __docformat__ = "restructuredtext en"
 
 import re
 import mailbox
+from itertools import combinations
 from rfc822 import parsedate
 
 from logilab.common.umessage import message_from_file
@@ -18,25 +19,6 @@ CLEANUP_RGX = re.compile(r'\bre\s*:', re.I|re.U)
 def cleanup_subject(string):
     return CLEANUP_RGX.sub('', string).strip()
 
-def combinaison(list):
-    """given a list return an iterator on possible combinaisons between all the
-    elements in the list but without identity:
-
-    >>> list(combinaison([1,2,3]))
-    [(1, 2), (2, 3), (1, 3)]
-    >>> list(combinaison([1,2,3,4]))
-    [(1, 2), (2, 3), (3, 4), (1,3), (1,4), (2,4)]
-
-    note: in python 2.6, this can be written:
-    >>> import itertools
-    >>> itertools.combinations([1,2,3], 2)
-    """
-    list = list[:]
-    while len(list) > 1:
-        first = list.pop()
-        for i in list:
-            yield (first, i)
-
 
 class StreamMailbox(mailbox.mbox):
     """A read-only mbox format mailbox from stream."""
@@ -174,7 +156,7 @@ class MBOXImporter(object):
                 self.import_message_parts(part, emaileid)
             if self._context == 'alternative':
                 alternatives = self._alternatives.pop()
-                for eid1, eid2 in combinaison(alternatives):
+                for eid1, eid2 in combinations(alternatives, 2):
                     self.execute('SET X alternative Y WHERE X eid %(x)s, Y eid %(y)s',
                                   {'x': eid1, 'y': eid2})
             self._context = None