def METHOD_NAME(self, context, option=None):
    "usage: show [all | <option>]"
    from . import utils
    opts = config.get_configured_options() if option is None else config.get_all_options()
    def show_options(fn):
        s = ''
        for opt in opts:
            if fn(opt):
                parts = opt.split('.')
                val = (opt, config.get_option(parts[0], parts[1], raw=True))
                s += "%s = %s\n" % val
        utils.page_string(s)
    if option == 'all' or option is None:
        show_options(lambda o: True)
    else:
        show_options(lambda o: o.startswith(option) or o.endswith(option))