diff --git a/git/repo/fun.py b/git/repo/fun.py
index e3a7bc57a..9d9f84545 100644
--- a/git/repo/fun.py
+++ b/git/repo/fun.py
@@ -35,7 +35,7 @@ def is_git_dir(d):
             There is the unlikely danger to throw if we see directories which just look like a worktree dir,
             but are none."""
     if osp.isdir(d):
-        if (osp.isdir(osp.join(d, 'objects')) or os.environ.has_key('GIT_OBJECT_DIRECTORY')) \
+        if (osp.isdir(osp.join(d, 'objects')) or 'GIT_OBJECT_DIRECTORY' in os.environ) \
            and osp.isdir(osp.join(d, 'refs')):
             headref = osp.join(d, 'HEAD')
             return osp.isfile(headref) or \