func packBytesSlice(bytes []byte, l int) []byte {
	len := packNum(reflect.ValueOf(l))
	return append(len, common.RightPadBytes(bytes, (l+31)/32*32)...)
}
packBytesSlice packs the given bytes as [L, V] as the canonical representation
bytes slice
package abi
import (
	"math/big"
	"reflect"
	"github.com/dappledger/AnnChain/eth/common"
	"github.com/dappledger/AnnChain/eth/common/math"
)