Q:

Docker compose with networks and "internal" property example

I tried to find example of usage "internal" property with a network declaration in docker-compose.yml v2.
Other words I search how to do this:
docker network create someName --internal

but in docker-compose.yml.
I get error when try to use this variant: 
version: '2'

services:
# services definition

networks:
  someName:
    internal: true

Error message:
The Compose file '.\docker-compose.yml' is invalid because:
networks.someName value Additional properties are not allowed ('internal' was unexpected)

A:

Upgrade to docker-compose 1.9 or later, internal networks are a new feature of the docker-compose.yml.
Instructions to upgrade are on the compose releases page.

