def to_x_bytes(bytes):
    """
    Take a number in bytes and return a human-readable string.

    :param bytes: number in bytes
    :type bytes: int
    :returns: a human-readable string
    """
    x_bytes = bytes
    power = 0
    while x_bytes >= 1000:
        x_bytes = x_bytes * 0.001
        power = power + 3
    if power == 0:
        return '%.0f bytes' % x_bytes
    if power == 3:
        return '%.0f kB' % x_bytes
    if power == 6:
        return '%.0f MB' % x_bytes
    if power == 9:
        return '%.0f GB' % x_bytes
    if power == 12:
        return '%.0f TB' % x_bytes
