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: gun.go
    path of file: ./repos/chainlink/integration-tests/load/vrfv2plus
    
    the code of the file until where you have to start completion: package loadvrfv2plus

import (
	"fmt"
	"math/big"
	"math/rand"

	"github.com/rs/zerolog"
	"github.com/smartcontractkit/wasp"

	vrfcommon "github.com/smartcontractkit/chainlink/integration-tests/actions/vrf/common"
	"github.com/smartcontractkit/chainlink/integration-tests/actions/vrf/v
    
func selectBillingType(billingType string) (bool, error) {
	switch vrfv2plus_config.BillingType(billingType) {
	case vrfv2plus_config.BillingType_Link:
		return false, nil
	case vrfv2plus_config.BillingType_Native:
		return true, nil
	case vrfv2plus_config.BillingType_Link_and_Native:
		return randBool(), nil
	default:
		return false, fmt.Errorf("invalid billing type: %s", billingType)
	}
}