def color_cvss(cvss):
    """Attribute a color to the CVSS score"""
    try:
        cvss = float(cvss)
    except:
        return None

    if cvss < 3:
        color = "green_3b"
    elif cvss <= 5:
        color = "yellow_1"
    elif cvss <= 7:
        color = "orange_1"
    elif cvss <= 8.5:
        color = "dark_orange"
    else:
        color = "red"
    return color