Samples not working

When I run the commands for the demo

composer demo-symmetric
composer demo-asymmetric

I get the following;

```
roy:zd29238 roy$ composer demo-symmetric

[Symfony\Component\Console\Exception\CommandNotFoundException]
Command "demo-symmetric" is not defined.

roy:zd29238 roy$ composer demo-asymmetric

[Symfony\Component\Console\Exception\CommandNotFoundException]
Command "demo-asymmetric" is not defined.

```

So are there any instructions missing in order to run these examples?