I have 2 tables who look like that.

class Tag(SQLObject):
    term = StringCol(length=64)
    category = IntCol(default=0);
    date_in = DateTimeCol(default=datetime.now)
    items = RelatedJoin('Item', intermediateTable='item_tag',
                        joinColumn='tag_id', otherColumn='item_id')

class Item(SQLObject):
    itemhash = StringCol(length=34, alternateID=True,
    link = StringCol(length=512, alternateID=True,
    title = UnicodeCol(length=96)
    summary = UnicodeCol(length=512)
    updated = DateTimeCol(default=datetime.now)
    relations_updated = DateTimeCol(default=datetime.now)
    category = IntCol(default=0)

    tags = RelatedJoin('Tag', intermediateTable='item_tag',
                       joinColumn='item_id', otherColumn='tag_id')

And I would like to do a request like this. 

    items = Item.select(
            Tag.q.term == tag,
            LEFTJOINOn(Item, item_tag, Item.q.id == item_id),
            LEFTJOINOn(Tag, item_tag, Tag.q.id == tag_id)

#SELECT * FROM item_tag LEFT JOIN tag ON tag_id = tag.id LEFT JOIN item ON item.id = item_id
#WHERE tag.term='apple';

The problem is, I don't have a class for the table item_tag and I don't know how to address it. 

Thanks for any solutions