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 call_process(cls, cmd):
        if cls.is_error:
            raise subprocess.CalledProcessError(-1, cmd=cmd, output="Couldn't call xset.")

        if cmd[1:] == ["q"]:
            track = cls.info[cls.index]
            output = "\n".join(track)
            return output