- the value of a bindparam() can be a callable, in which

- the value of a bindparam() can be a callable, in which
case it's evaluated at statement execution time to
get the value.
- expressions used in filter(), filter_by() and others,
when they make usage of a clause generated from a
relation using the identity of a child object
(e.g. filter(Parent.child==<somechild>)), evaluate
the actual primary key value of <somechild> at
execution time so that the autoflush step of the
Query can complete, thereby populating the PK value
of <somechild> in the case that <somechild> was
pending.
- cleanup of attributes.get_committed_value() to never return
the NO_VALUE value; evaluates to None