@classmethod
def lookup_category(cls, value):
    """Given the Nyaa category in number, underscore, number form,
        return the appropriate :class:`Category`, or `None`.

        :param value: Nyaa category in `number_number` form (eg: '1_0')
        :return: :class:`Category` or `None`
        """
    return cls._value2member_map_.get(value, None)
