run_simulation = OpenMMSimulation ( " run_simulation " ) run_simulation . timestep = 1.0 * u n i t . femtosecond run_simulation . ensemble = Ensemble . NPT a n a l y s i s = E x t r a c t A v e r a g e S t a t i s t i c ( " e x t r a c t _ d e n s i t y " ) a n a l y s i s . s t a t i s t i c s = ProtocolPath ( " s t a t i s t i c s _ p a t h " , " run_simulation " )