Update the python demo with callbacks
Update the python demo with callbacks

rserban/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,dariomangoni/chrono,projectchrono/chrono,rserban/chrono,dariomangoni/chrono,rserban/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,rserban/chrono,dariomangoni/chrono,rserban/chrono,dariomangoni/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono,Milad-Rakhsha/chrono,projectchrono/chrono,rserban/chrono,dariomangoni/chrono,projectchrono/chrono,dariomangoni/chrono,projectchrono/chrono,rserban/chrono