diff --git a/hggit/git2hg.py b/hggit/git2hg.py
index ad0bad8a0700535ec6767a2b0a2a5f656611ecd7_aGdnaXQvZ2l0MmhnLnB5..342b58e452091aea24b92e4d63059651ac5ba9c9_aGdnaXQvZ2l0MmhnLnB5 100644
--- a/hggit/git2hg.py
+++ b/hggit/git2hg.py
@@ -37,7 +37,6 @@
     # traverse the heads getting a list of all the unique commits in
     # topological order
     commits = []
-    seen = set(todo)
     while todo:
         sha = todo[-1]
         if sha in done or sha in git_map: