You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: complaint.go
    path of file: ./repos/gopay/wechat/v3
    
    the code of the file until where you have to start completion: package wechat

import (
	"context"
	"encoding/json"
	"fmt"
	"net/http"

	"github.com/go-pay/gopay"
)

// 创建投诉通知回调地址API
// Code = 0 is success
func (c *ClientV3) V3ComplaintNotifyUrlCreate(ctx context.Context, url string) (wxRsp *ComplaintNotifyUrlRsp, err error) {
	bm := make(gopay.BodyMap)
	bm.Set("url", url)
	authorization,
    
func (c *ClientV3) V3ComplaintNotifyUrlDelete(ctx context.Context) (wxRsp *EmptyRsp, err error) {
	authorization, err := c.authorization(MethodDelete, v3ComplaintNotifyUrlDelete, nil)
	if err != nil {
		return nil, err
	}
	res, si, bs, err := c.doProdDelete(ctx, nil, v3ComplaintNotifyUrlDelete, authorization)
	if err != nil {
		return nil, err
	}
	wxRsp = &EmptyRsp{Code: Success, SignInfo: si}
	if res.StatusCode != http.StatusNoContent {
		wxRsp.Code = res.StatusCode
		wxRsp.Error = string(bs)
		return wxRsp, nil
	}
	return wxRsp, c.verifySyncSign(si)
}