Chapter 7: no mining happening?

[tindandelion]

Going through the chapter 7's code in order to understand how the whole app works, I've been surprised to find out that no mining is actually happening anywhere in the code. There's a method Blockchain.mine_new_block() but it doesn't seem to be called from anywhere.

The node can:

• Receive a block from another node;
• Receive a transaction and add it to pending transactions list.

But nowhere in the code do we create a new block, apart from the genesis. That's confusing.