progval@Andromede:~/repositories$ pythonPython 2.7.3rc2 (default, Mar 21 2012, 06:59:11) [GCC 4.6.3] on linux2Type "help", "copyright", "credits" or "license" for more information.>>> import git>>> git.Repo('testing.git').tree()Traceback (most recent call last):  File "<stdin>", line 1, in <module>  File "/usr/local/lib/python2.7/dist-packages/git/repo/base.py", line 399, in tree    return self.head.commit.tree  File "/usr/local/lib/python2.7/dist-packages/git/refs/symbolic.py", line 168, in _get_commit    obj = self._get_object()  File "/usr/local/lib/python2.7/dist-packages/git/refs/symbolic.py", line 161, in _get_object    return Object.new_from_sha(self.repo, hex_to_bin(self.dereference_recursive(self.repo, self.path)))  File "/usr/local/lib/python2.7/dist-packages/git/refs/symbolic.py", line 115, in dereference_recursive    hexsha, ref_path = cls._get_ref_info(repo, ref_path)  File "/usr/local/lib/python2.7/dist-packages/git/refs/symbolic.py", line 142, in _get_ref_info    raise ValueError("Reference at %r does not exist" % ref_path)ValueError: Reference at 'refs/heads/master' does not exist