def __init__(self, groups=None):
        super(GroupedRequirements, self).__init__(NamedRequirements)
        self.groups = groups or self.default_groups
        self.filename = None
        self.create_default_groups()
def finalize_options(self):
    self.set_undefined_options('install',
                               ('install_headers', 'install_dir'),
                               ('force', 'force'))