Creating empties with {} takes just 58% of the time as dict() [0.25 us, 0.39 us] because there's no need to LOAD_GLOBAL and CALL_FUNCTION. 'not not variable' i

Creating empties with {} takes just 58% of the time as dict() [0.25 us, 0.39 us] because there's no need to LOAD_GLOBAL and CALL_FUNCTION. 'not not variable' is similarly faster than bool(variable). (not that I've run into this often in Python.)