import binascii


def _FormatAsUint64LittleEndian(s):
  """Formats a string as uint64 value in little endian order."""
  for _ in range(len(s), 8):
    s += b'\0'
  s = s[::-1]  # Reverse the string
  return b'0x%s' % binascii.b2a_hex(s)