def METHOD_NAME(default="Unknown"):
    """Return the CPU codename."""
    cpu_model = get_cpu_model_name()
    vendor = get_cpu_vendor()
    if vendor == CpuVendor.INTEL:
        result = re.match(r"^(.*) @.*$", cpu_model)
        if result:
            return CPU_DICT[CpuVendor.INTEL].get(result.group(1), default)
    if vendor == CpuVendor.AMD:
        result = re.match(r"^(.*) [0-9]*-Core Processor$", cpu_model)
        if result:
            return CPU_DICT[CpuVendor.AMD].get(result.group(1), default)
    if vendor == CpuVendor.ARM:
        return cpu_model
    return default