modified_unstaged_files includes....everything?

[miketwo]

From a clean clone of the gittle repo:

In [1]: from gittle import Gittle
In [2]: import os
In [3]: repo = Gittle(os.getcwd())
In [5]: repo.modified_unstaged_files
Out[5]: 
{'.gitignore',
 'LICENSE',
 'README.md',
 'examples/base.py',
 'examples/clone.py',
 'examples/clone_bare.py',
 'examples/commit.py',
 'examples/complete.py',
 'examples/config.py',
 'examples/diff.py',
 'examples/fork.py',
 'examples/mv.py',
 'examples/paths.py',
 'examples/pull.py',
 'examples/push.py',
 'examples/server.py',
 'examples/status.py',
 'examples/versions.py',
 'gittle/__init__.py',
 'gittle/auth.py',
 'gittle/exceptions.py',
 'gittle/gittle.py',
 'gittle/server.py',
 'gittle/utils/__init__.py',
 'gittle/utils/git.py',
 'gittle/utils/paths.py',
 'gittle/utils/urls.py',
 'setup.py',
 'sitecustomize.py'}

In [6]: repo.modified_files
Out[6]: set()

Is this expected behaviour?