func createEmptyDB() error {
	ctx := context.Background()
	db, err := walletdb.Create("bdb", emptyDbPath)
	defer db.Close()
	if err != nil {
		return err
	}
	err = Initialize(ctx, db, chaincfg.TestNet3Params(), seed, pubPassphrase,
		privPassphrase)
	if err != nil {
		return err
	}
	err = Upgrade(ctx, db, pubPassphrase, chaincfg.TestNet3Params())
	if err != nil {
		return err
	}
	return nil
}
createEmptyDB is a helper function for creating an empty wallet db.
package udb
import (
	"context"
	"encoding/hex"
	"fmt"
	"os"
	"decred.org/dcrwallet/v2/wallet/walletdb"
	"github.com/decred/dcrd/chaincfg/v3"
)
var (
	seed = []byte{
		0xb4, 0x6b, 0xc6, 0x50, 0x2a, 0x30, 0xbe, 0xb9, 0x2f,
		0x0a, 0xeb, 0xc7, 0x76, 0x40, 0x3c, 0x3d, 0xbf, 0x11,
		0xbf, 0xb6, 0x83, 0x05, 0x96, 0x7c, 0x36, 0xda, 0xc9,
		0xef, 0x8d, 0x64, 0x15, 0x67,
	}
	emptyDbPath = ""
	pubPassphrase   = []byte("_DJr{fL4H0O}*-0\n:V1izc)(6BomK")
	privPassphrase  = []byte("81lUHXnOMZ@?XXd7O9xyDIWIbXX-lj")
	pubPassphrase2  = []byte("-0NV4P~VSJBWbunw}%<Z]fuGpbN[ZI")
	privPassphrase2 = []byte("~{<]08%6!-?2s<$(8$8:f(5[4/!/{Y")
)
func hexToBytes(origHex string) []byte {
	buf, err := hex.DecodeString(origHex)
	if err != nil {
		panic(err)
	}
	return buf
}