Vagrant Change default ssh forwarded port

Vagrant is a great tool for quickly setting up and destroying a development test environment. By default it will define a local port on your workstation to port forward ssh traffic to the Vagrant box. For a multi server set-up environment I prefer to be able to specify the exact port to use for ssh port forwarding.
For example to set the ssh port forwarding as 4001 in the Vagrantfile you can define :

db.vm.network "forwarded_port", guest: 22, host: 4001, id: 'ssh'

It does require the id: section to be set for ssh. I find this really useful for Ansible so I can define the exact ssh port and IP address within my Ansible File.