def _register(cls,
                  app,
                  base_route=None,
                  subdomain=None,
                  route_prefix=None,
                  trailing_slash=True):
        """Registers a Mocha class for use with a specific instance of a
        Flask app. Any methods not prefixes with an underscore are candidates
        to be routed and will have routes registered when this method is
        called.

        :param app: an instance of a Flask application

        :param base_route: The base path to use for all routes registered for
                           this class. Overrides the base_route attribute if
                           it has been set.

        :param subdomain:  A subdomain that this registration should use when
                           configuring routes.

        :param route_prefix: A prefix to be applied to all routes registered
                             for this class. Precedes base_route. Overrides
                             the class' route_prefix if it has been set.
        """

        if cls is Mocha:
            raise TypeError("cls must be a subclass of Mocha, not Mocha itself")

        # Create a unique namespaced key to access view.
        # $module.$class_name.$Method
        module = cls.__module__.split(".")[-1]

        if not hasattr(views, module):
            setattr(views, module, type('', (), {}))
        mod = getattr(views, module)
        setattr(mod, cls.__name__, cls)

        if base_route:
            cls.orig_base_route = cls.base_route
            cls.base_route = base_route

        if route_prefix:
            cls.orig_route_prefix = cls.route_prefix
            cls.route_prefix = route_prefix

        if not subdomain:
            if hasattr(app, "subdomain") and app.subdomain is not None:
                subdomain = app.subdomain
            elif hasattr(cls, "subdomain"):
                subdomain = cls.subdomain

        if trailing_slash is not None:
            cls.orig_trailing_slash = cls.trailing_slash
            cls.trailing_slash = trailing_slash

        for name, value in get_interesting_members(Mocha, cls):
            proxy = cls.make_proxy_method(name)
            route_name = build_endpoint_route_name(cls, name)
            try:
                if hasattr(value, "_rule_cache") and name in value._rule_cache:
                    for idx, cached_rule in enumerate(value._rule_cache[name]):
                        rule, options = cached_rule
                        rule = cls.build_rule(rule)
                        sub, ep, options = cls.parse_options(options)

                        if not subdomain and sub:
                            subdomain = sub

                        if ep:
                            endpoint = ep
                        elif len(value._rule_cache[name]) == 1:
                            endpoint = route_name
                        else:
                            endpoint = "%s_%d" % (route_name, idx,)

                        app.add_url_rule(rule, endpoint, proxy,
                                         subdomain=subdomain,
                                         **options)
                elif name in cls.__special_methods:
                    if name in ["get", "index"]:
                        methods = ["GET"]
                        if name == "index":
                            if hasattr(value, "_methods_cache"):
                                methods = value._methods_cache
                    else:
                        methods = [name.upper()]

                    rule = cls.build_rule("/", value)
                    if not cls.trailing_slash:
                        rule = rule.rstrip("/")
                    app.add_url_rule(rule, route_name, proxy,
                                     methods=methods,
                                     subdomain=subdomain)

                else:
                    methods = value._methods_cache \
                        if hasattr(value, "_methods_cache") \
                        else ["GET"]

                    name = utils.dasherize(name)
                    route_str = '/%s/' % name
                    if not cls.trailing_slash:
                        route_str = route_str.rstrip('/')
                    rule = cls.build_rule(route_str, value)
                    app.add_url_rule(rule, route_name, proxy,
                                     subdomain=subdomain,
                                     methods=methods)
            except DecoratorCompatibilityError:
                raise DecoratorCompatibilityError(
                    "Incompatible decorator detected on %s in class %s" % (name, cls.__name__))

        if hasattr(cls, "orig_base_route"):
            cls.base_route = cls.orig_base_route
            del cls.orig_base_route

        if hasattr(cls, "orig_route_prefix"):
            cls.route_prefix = cls.orig_route_prefix
            del cls.orig_route_prefix

        if hasattr(cls, "orig_trailing_slash"):
            cls.trailing_slash = cls.orig_trailing_slash
            del cls.orig_trailing_slash