[web2py] TR and TD

[praveen krishna]

Hii,
     What does TR and TD do in the function 
 def records():
    'show all recors in plugin_seq db to user'
    records = db(db.plugin_seq.id>0).select()
    items = []
    for record in records:
        items.append(TR(TD(record.filename)(TD('del'))))
    return TABLE(items)
 and what does actually TR and TD mean.