code: def rbac_policy_update(request, policy_id, **kwargs):
      
      body = {'rbac_policy': kwargs}
      rbac_policy = neutronclient(request).update_rbac_policy(
          policy_id, body=body).get('rbac_policy')
      return RBACPolicy(rbac_policy)
docs: Update a RBAC Policy.
  
      :param request: request context
      :param policy_id: target policy id
      :param target_tenant: target tenant of the policy
      :return: RBACPolicy object