https://github.com/alfiopuglisi/guietta
换一种简单的方式写 GUI（图形用户界面）程序。
```
from guietta import _, Gui, Quit
gui = Gui(
[ "Enter numbers:", "__a__", "+", "__b__", ["Calculate"] ],
[ "Result: -->", "result", _, _, _ ],
[ _, _, _, _, Quit ]
)

with gui.Calculate:
gui.result = float(gui.a) + float(gui.b)

gui.run()
```
直观易懂