def get_installed_pypackages():
    return {p.project_name.lower(): p for p in pkg_resources.working_set}
def __init__(self, root, cwd, files, badfn=None):
        super(exactmatcher, self).__init__(root, cwd, badfn)

        if isinstance(files, list):
            self._files = files
        else:
            self._files = list(files)