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: types.go
    path of file: ./repos/evcc/vehicle/nissan
    
    the code of the file until where you have to start completion: package nissan

import (
	"fmt"
	"strings"
	"time"
)

type Auth struct {
	AuthID    string         `json:"authId"`
	Template  string 
    
func (ct *Timestamp) UnmarshalJSON(data []byte) error {
	s := strings.Trim(string(data), "\"")

	t, err := time.Parse(timeFormat, s)
	if err == nil {
		ct.Time = t
	}

	return err
}