In a typical development cycle, we will start to develop the application after we have planned out the requirements. However, since we are in learning mode and already know of a reference application, it would be smart of us to examine the simple_switch_13.py application as a starting point. Based on what we've seen, we can also tweak or make our own code based on this reference to help us understand the Ryu framework better. Let's make a separate folder called mastering_python_networking under /home/ubuntu/ryu and store our file in there:
$ mkdir mastering_python_networking
In the folder, you can copy and paste the following code, from chapter10_1.py:
from ryu.base import app_managerfrom ryu.controller import ofp_event ...
