sending packet onto dummy network device but receiving echo

[Vadanane]

It depends on what you are trying to do. If you are trying to create a web application, then you will need to use a web framework such as Django or Flask. If you are trying to create a desktop application, then you will need to use a GUI library such as Tkinter or PyQt. If you are trying to create a game, then you will need to use a game engine such as Pygame or Unity.