def register(self, prefix, viewset, base_name=None):
        """Add any registered route into a global API directory.

        If the prefix includes a path separator,
        store the URL in the directory under the first path segment.
        Otherwise, store it as-is.

        For example, if there are two registered prefixes,
        'v1/users' and 'groups', `directory` will look liks:

        {
            'v1': {
                'users': {
                    '_url': 'users-list'
                    '_viewset': <class 'UserViewSet'>
                },
            }
            'groups': {
               '_url': 'groups-list'
               '_viewset': <class 'GroupViewSet'>
            }
        }
        """
        if base_name is None:
            base_name = prefix

        super(DynamicRouter, self).register(prefix, viewset, base_name)

        prefix_parts = prefix.split('/')
        if len(prefix_parts) > 1:
            prefix = prefix_parts[0]
            endpoint = '/'.join(prefix_parts[1:])
        else:
            endpoint = prefix
            prefix = None

        if prefix and prefix not in directory:
            current = directory[prefix] = {}
        else:
            current = directory.get(prefix, directory)

        list_name = self.routes[0].name
        url_name = list_name.format(basename=base_name)
        if endpoint not in current:
            current[endpoint] = {}
        current[endpoint]['_url'] = url_name
        current[endpoint]['_viewset'] = viewset
Add any registered route into a global API directory.

        If the prefix includes a path separator,
        store the URL in the directory under the first path segment.
        Otherwise, store it as-is.

        For example, if there are two registered prefixes,
        'v1/users' and 'groups', `directory` will look liks:

        {
            'v1': {
                'users': {
                    '_url': 'users-list'
                    '_viewset': <class 'UserViewSet'>
                },
            }
            'groups': {
               '_url': 'groups-list'
               '_viewset': <class 'GroupViewSet'>
            }
        }