<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def _get_unscheduled_routers(self, plugin, context):
 """Get routers with no agent binding."""

        if NEUTRON_VERSION.version[0] <= NEUTRON_NEWTON_VERSION.version[0]:
            context, plugin = plugin, context
        # TODO(gongysh) consider the disabled agent's router
        no_agent_binding = ~sql.exists().where(
            bc.Router.id == bc.rb_model.RouterL3AgentBinding.router_id)
        # Modified to only include routers of network namespace type
        ns_routertype_id = plugin.get_namespace_router_type_id(context)
        query = context.session.query(bc.Router.id)
        query = query.join(l3_models.RouterHostingDeviceBinding)
        query = query.filter(
            l3_models.RouterHostingDeviceBinding.router_type_id ==
            ns_routertype_id, no_agent_binding)
        unscheduled_router_ids = [router_id_[0] for router_id_ in query]
        if unscheduled_router_ids:
            return plugin.get_routers(
                context, filters={'id': unscheduled_router_ids})
        return []