how to implement a RESTClientGetter for helm action pkg

restclient.go

package main

import (
    "k8s.io/apimachinery/pkg/api/meta"
    "k8s.io/client-go/discovery"
    "k8s.io/client-go/discovery/cached/memory"
    "k8s.io/client-go/rest"
    "k8s.io/client-go/restmapper"
    "k8s.io/client-go/tools/clientcmd"
    "k8s.io/client-go/tools/clientcmd/api"
)

type RESTClientGetter struct {
    clientconfig clientcmd.ClientConfig
}

func NewRESTClientGetter(kubeconfig string, namespace string) (*RESTClientGetter, error) {
    clientconfig, err := clientcmd.NewClientConfigFromBytes([]byte(kubeconfig))
    if err != nil {
        return nil, err
    }

    rawconfig, err := clientconfig.RawConfig()
    if err != nil {
        return nil, err
    }

    clientconfig = clientcmd.NewDefaultClientConfig(rawconfig, &clientcmd.ConfigOverrides{
        Context: api.Context{
            Namespace: namespace,
        },
    })

    return &RESTClientGetter{clientconfig}, nil
}

func (r *RESTClientGetter) ToRESTConfig() (*rest.Config, error) {
    return r.clientconfig.ClientConfig()
}

func (r *RESTClientGetter) ToDiscoveryClient() (discovery.CachedDiscoveryInterface, error) {
    restconfig, err := r.clientconfig.ClientConfig()
    if err != nil {
        return nil, err
    }
    dc, err := discovery.NewDiscoveryClientForConfig(restconfig)
    if err != nil {
        return nil, err
    }
    return memory.NewMemCacheClient(dc), nil
}

func (r *RESTClientGetter) ToRESTMapper() (meta.RESTMapper, error) {
    dc, err := r.ToDiscoveryClient()
    if err != nil {
        return nil, err
    }
    return restmapper.NewDeferredDiscoveryRESTMapper(dc), nil
}

func (r *RESTClientGetter) ToRawKubeConfigLoader() clientcmd.ClientConfig {
    return r.clientconfig
}