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: decode.go
    path of file: ./repos/agones/vendor/github.com/aws/aws-sdk-go/aws/endpoints
    
    the code of the file until where you have to start completion: package endpoints

import (
	"encoding/json"
	"fmt"
	"io"

	"github.com/aws/aws-sdk-go/aws/awserr"
)

type modelDefinition map[string]json.RawMessage

// A DecodeModelOptions are the options for how the endpoints model definition
// are decoded.
type DecodeModelOptions struct {
	SkipCustomizations bool
}

// Set combines all of the option functions together.
func (d *DecodeModelOptions) Set(optFns ...func(*DecodeModelOptions)) {
	
    
func decodeV3Endpoints(modelDef modelDefinition, opts DecodeModelOptions) (Resolver, error) {
	b, ok := modelDef["partitions"]
	if !ok {
		return nil, newDecodeModelError("endpoints model missing partitions", nil)
	}

	ps := partitions{}
	if err := json.Unmarshal(b, &ps); err != nil {
		return nil, newDecodeModelError("failed to decode endpoints model", err)
	}

	if opts.SkipCustomizations {
		return ps, nil
	}

	// Customization
	for i := 0; i < len(ps); i++ {
		p := &ps[i]
		custRegionalS3(p)
		custRmIotDataService(p)
		custFixAppAutoscalingChina(p)
		custFixAppAutoscalingUsGov(p)
	}

	return ps, nil
}