In [ ]:
def iris(petallength, petalwidth):
    if petalwidth <= .08:
        if petalwidth <= 1.75 and petallength <= 4.95:
            if petalwidth <= 1.65:
                return 'class2'
            else:
                return 'class3'
        else:
            return 'class3'
    else:
        return 'class1'