'Returns the default :class:`~horizon.Dashboard` instance.
If ``"default_dashboard"`` is specified in ``HORIZON_CONFIG``
then that dashboard will be returned. If not, the first dashboard
returned by :func:`~horizon.get_dashboards` will be returned.'

def get_default_dashboard(self):

    if self.default_dashboard:
        return self._registered(self.default_dashboard)
    elif len(self._registry):
        return self.get_dashboards()[0]
    else:
        raise NotRegistered('No    dashboard    modules    have    been    registered.')
