1. Use Wxpython to draw Electrical Power Distribution Network as shown in picture, but more devices (shapes) should be connected on each node, such as spot transformers, load( different shapes);
2. have mouse wheel zoom in/out function
3. mouse detection on device and left click to open dialogue for each device.
4. don't use those existing packages such as networkx or floatcanvas since they are not suitable.
5. Keep code as simple and flexible as possible