With all of the libraries installed and the Python code modified, our app is ready to accept calls and record voicemails. But it can’t quite do that just yet. There’s one more step: Twilio actually needs to know where on the internet the Raspberry Pi is running. Since this is a local server, that’s a bit tricky, but there’s a simple solution called Ngrok.
So, I finally did it. Here’s my process for developing a professional voicemail message in 10 steps:

“Hey listen, I don’t know what I can tell you. There’s nobody here right now, ya know? But if you turkeys want to leave your name and your number, I mean all I can do is pass it onto them, ya know what I mean? Of course, if you don’t want to, it’s no big deal, just don’t ever call here again.”
Is your refrigerator running? You better go catch it! Corny jokes like this don't work anymore...and won't work in your voicemail greeting. Saying things like, "Hello, you've reach the machine that lives inside Mark's cell phone. Leave a message and I'll tell him!" are really unappealing and aren't even funny.