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: fake_jws.go
    path of file: ./repos/oapi-codegen/examples/authenticated-api/echo/server
    
    the code of the file until where you have to start completion: package server

import (
	"crypto/ecdsa"
	"fmt"

	"github.com/deepmap/oapi-codegen/v2/pkg/ecdsafile"
	"github.com/lestrrat-go/jwx/jwa"
	"github.com/lestrrat-go/jwx/jwk"
	"github.com/lestrrat-go/jwx/jws"
	"github.com/lestrrat-go/jwx/jwt"
)

// PrivateKey is an ECDSA private key which was generated with the following
// command:
//     openssl ecparam -name prime256v1 -genkey -no
    
func NewFakeAuthenticator() (*FakeAuthenticator, error) {
	privKey, err := ecdsafile.LoadEcdsaPrivateKey([]byte(PrivateKey))
	if err != nil {
		return nil, fmt.Errorf("loading PEM private key: %w", err)
	}

	set := jwk.NewSet()
	pubKey := jwk.NewECDSAPublicKey()

	err = pubKey.FromRaw(&privKey.PublicKey)
	if err != nil {
		return nil, fmt.Errorf("parsing jwk key: %w", err)
	}

	err = pubKey.Set(jwk.AlgorithmKey, jwa.ES256)
	if err != nil {
		return nil, fmt.Errorf("setting key algorithm: %w", err)
	}

	err = pubKey.Set(jwk.KeyIDKey, KeyID)
	if err != nil {
		return nil, fmt.Errorf("setting key ID: %w", err)
	}

	set.Add(pubKey)

	return &FakeAuthenticator{PrivateKey: privKey, KeySet: set}, nil
}