def process_normalization(cls, parse_group):
        """
        Given a normalization parse group (i.e. the contents of the
        braces), validate the option list and compute the appropriate
        integer value for the normalization plotting option.
        """
        if ('norm_options' not in parse_group): return None
        opts = parse_group['norm_options'][0].asList()
        if opts == []: return None

        options = ['+framewise', '-framewise', '+axiswise', '-axiswise']

        for normopt in options:
            if opts.count(normopt) > 1:
                raise SyntaxError("Normalization specification must not"
                                  " contain repeated %r" % normopt)

        if not all(opt in options for opt in opts):
            raise SyntaxError("Normalization option not one of %s"
                              % ", ".join(options))
        excluded = [('+framewise', '-framewise'), ('+axiswise', '-axiswise')]
        for pair in excluded:
            if all(exclude in opts for exclude in pair):
                raise SyntaxError("Normalization specification cannot"
                                  " contain both %s and %s" % (pair[0], pair[1]))

        # If unspecified, default is -axiswise and -framewise
        if len(opts) == 1 and opts[0].endswith('framewise'):
            axiswise = False
            framewise = True if '+framewise' in opts else False
        elif len(opts) == 1 and opts[0].endswith('axiswise'):
            framewise = False
            axiswise = True if '+axiswise' in opts else False
        else:
            axiswise = True if '+axiswise' in opts else False
            framewise = True if '+framewise' in opts else False

        return dict(axiswise=axiswise,
                    framewise=framewise)