def reverse_hex(input_hex):
    """Reverse a HEX string, treating 2 chars as a byte.

    Expected results look like this:
    reverse_hex('abcdef') = 'efcdab'

    Args:
        input_hex (str): Input string in hex which needs to be converted.

    Returns:
        Hex string reversed.
    """
    return "".join([input_hex[x: x + 2] for x in range(0, len(input_hex), 2)][::-1])