How to use the djangoql.schema.IntField function in djangoql

def get_fields(self, model):
        fields = super(UserQLSchema, self).get_fields(model)
        if model == User:
            fields = [UserAgeField(), IntField(name='groups_count')] + fields
        return fields

class BookQLSchema(DjangoQLSchema):
    suggest_options = {
        Book: ['genre'],
    }


@admin.register(Book)
class BookAdmin(DjangoQLSearchMixin, admin.ModelAdmin):
    djangoql_schema = BookQLSchema
    list_display = ('name', 'author', 'genre', 'written', 'is_published')
    list_filter = ('is_published',)
    filter_horizontal = ('similar_books',)


class UserAgeField(IntField):
    """
    Search by given number of full years
    """
    model = User
    name = 'age'

    def get_lookup_name(self):
        """
        We'll be doing comparisons vs. this model field
        """
        return 'date_joined'

    def get_lookup(self, path, operator, value):
        if operator == 'in':
            result = None
            for year in value:

def get_field_cls(self, field):
        str_fields = (models.CharField, models.TextField, models.UUIDField)
        if isinstance(field, str_fields):
            return StrField
        elif isinstance(field, (models.AutoField, models.IntegerField)):
            return IntField
        elif isinstance(field, (models.BooleanField, models.NullBooleanField)):
            return BoolField
        elif isinstance(field, (models.DecimalField, models.FloatField)):
            return FloatField
        elif isinstance(field, models.DateTimeField):
            return DateTimeField
        elif isinstance(field, models.DateField):
            return DateField
        return DjangoQLField