How to pass env variables when starting a container?

[valovm]

I triesd:
pass as Hash - it is not working
Docker::Container.create('Image' => image_name, 'Env'=> { 'a' => '123'})

pass as String - it is not working
Docker::Container.create('Image' => image_name, 'Env'=> 'a=123')

What way is correct?

[ls-todd-lunter]

It should be 'Env' => ['KEY=value', 'KEY=value']