def __init__(self, name, filename=None):
        self.name = name
        super(NamedRequirements, self).__init__(filename=filename)
def files(self):
        """Explicitly listed files or patterns or roots:
        if no patterns or .always(): empty list,
        if exact: list exact files,
        if not .anypats(): list all files and dirs,
        else: optimal roots"""
        return self._files