count() method added to collection attributes: Group[123].students.count() or count(Group[123].students)
is_empty() method added to collections: Group[123].students.is_empty()
Caching result of collection.count() and collection.is_empty()
Optimization: use None instead of NOT_LOADED for setdata
Merge master into orm: collection.count() and collection.is_empty() methods
New pagination method Query.page:
select(...).page(3, pagesize=10) -> LIMIT 10 OFFSET 20
select(...).page(pagenum=3, pagesize=20) -> LIMIT 20 OFFSET 40
select(...).page(3) -> LIMIT 10 OFFSET 20  # pagesize=10 by default
Merge master into orm: Query.page() method