class Student(object):
    def __init__(self, name, gender):
        self.__name = name
        self.__gender = gender

    def get_name(self):
        return self.__name

    def set_name(self, name):
        if name.isalpha() is True:
            self.__name = name
        else:
            raise ValueError('请输入正确的姓名(只包含字母)!')

    def get_gender(self):
        return self.__gender

    def set_gender(self, gender):
        if gender in ['male', 'female']:
            self.__gender = gender
        else:
            raise ValueError('请输入正确的性别(male/female)!')


zig =  Student('zig', 'male')
print(zig.get_name(), 'is', zig.get_gender())
zig.set_name('su')
zig.set_gender('female')
print(zig.get_name(), 'is', zig.get_gender())