code: func Byte(bigint *big.Int, padlength, n int) byte {
  	if n >= padlength {
  		return byte(0)
  	}
  	return bigEndianByteAt(bigint, padlength-1-n)
  }
docs: // Byte returns the byte at position n,
  // with the supplied padlength in Little-Endian encoding.
  // n==0 returns the MSB
  // Example: bigint '5', padlength 32, n=31 => 5