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: config.go
    path of file: ./repos/kubernetes/vendor/github.com/google/cadvisor/perf
    
    the code of the file until where you have to start completion: // Copyright 2020 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required b
    
func (g *Group) UnmarshalJSON(b []byte) error {
	var jsonObj interface{}
	err := json.Unmarshal(b, &jsonObj)
	if err != nil {
		return err
	}
	switch obj := jsonObj.(type) {
	case string:
		*g = Group{
			events: []Event{Event(obj)},
			array:  false,
		}
		return nil
	case []interface{}:
		group := Group{
			events: make([]Event, 0, len(obj)),
			array:  true,
		}
		for _, v := range obj {
			value, ok := v.(string)
			if !ok {
				return fmt.Errorf("cannot unmarshal %v", value)
			}
			group.events = append(group.events, Event(value))
		}
		*g = group
		return nil
	}
	return fmt.Errorf("unsupported type")
}