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: conv.go
    path of file: ./repos/teller/vendor/github.com/cloudflare/circl/internal/conv
    
    the code of the file until where you have to start completion: package conv

import (
	"encoding/binary"
	"fmt"
	"math/big"
	"strings"
)

// BytesLe2Hex returns an hexadecimal string of a number stored in a
// little-endian order slice x.
func BytesLe2Hex(x []byte) string {
	b := &strings.Builde
    
func BigInt2BytesLe(z []byte, x *big.Int) {
	xLen := (x.BitLen() + 7) >> 3
	zLen := len(z)
	if zLen >= xLen && x.Sign() >= 0 {
		y := x.Bytes()
		for i := 0; i < xLen; i++ {
			z[i] = y[xLen-1-i]
		}
		for i := xLen; i < zLen; i++ {
			z[i] = 0
		}
	}
}