X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~mdw/git/catacomb-python/blobdiff_plain/c968103a2e2fe9f34cb6af04208efc9883eab361..1b61856d4b3feef4f3cd810da2ef8bf3e54d6041:/catacomb/__init__.py

diff --git a/catacomb/__init__.py b/catacomb/__init__.py
index 43d74d9..022c5f9 100644
--- a/catacomb/__init__.py
+++ b/catacomb/__init__.py
@@ -531,9 +531,12 @@ class _groupmap (object):
   def __init__(me, map, nth):
     me.map = map
     me.nth = nth
-    me.i = [None] * (max(map.values()) + 1)
+    me._n = max(map.values()) + 1
+    me.i = me._n*[None]
   def __repr__(me):
     return '{%s}' % ', '.join(['%r: %r' % (k, me[k]) for k in me])
+  def __len__(me):
+    return me._n
   def __contains__(me, k):
     return k in me.map
   def __getitem__(me, k):