django def validate_column和validate

class RegUserSet(mixins.CreateModelMixin,viewsets.GenericViewSet):
    serializer_class = RegUserSerializer
    # queryset = User.objects.all()

class RegUserSerializer(serializers.ModelSerializer):
    code = serializers.CharField(required=True, max_length=10, write_only=True)
    mobile = serializers.CharField(max_length=11, allow_null=True)
    password = serializers.CharField(write_only=True)

    def validate_code(self, code):
        mobile = self.initial_data[‘username‘]
        codes = VerifyCode.objects.filter(mobile=mobile).order_by(‘-add_time‘)
        if codes:
            dbcode = codes[0]
            if dbcode.code != code:
                raise serializers.ValidationError("验证码不正确")
            if dbcode.add_time.replace(tzinfo=None) < datetime.datetime.now() - datetime.timedelta(days=0, minutes=5,
                                                                                                   seconds=0):
                raise serializers.ValidationError("验证码过期")
        else:
            raise serializers.ValidationError(‘验证码不正确‘)
        return code

    def validate(self, attrs):
        attrs[‘mobile‘] = attrs[‘username‘]
        del attrs[‘code‘]
        return attrs

    def create(self, validated_data):
        user = super(RegUserSerializer, self).create(validated_data)
        user.set_password(validated_data[‘password‘])
        user.save()
        return user

    class Meta:
        model = User
        fields = (‘username‘, ‘password‘, ‘mobile‘, ‘code‘)