ModelStructure

In PyDataColl there are three type of model: DEVICE, TERM, ITEM. their relationship can be shown as this:

Device1:
    ->Term1:
        ->Item1
        ->Item2
        ->...
    ->Term2:
        ->Item1
        ->...
    ->...
Device2:
    ->Term3
        ...

Device

not done yet:(

Term

not done yet:(

Item

not done yet:(