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: error.go
    path of file: ./repos/gopay/saobei
    
    the code of the file until where you have to start completion: package saobei

import (
	"fmt"
)

// BizErr 用于判断通联的业务逻辑是否有错误
type Bi
    
func bizErrCheck(resp RspBase) error {
	if resp.ReturnCode != "01" {
		return &BizErr{
			Code: resp.ReturnCode,
			Msg:  resp.ReturnMsg,
		}
	}
	//if resp.ResultCode != "01" {
	//	return &BizErr{
	//		Code: resp.ResultCode,
	//		Msg:  resp.ReturnMsg,
	//	}
	//}
	return nil
}