class Thing
  include Her::Model

  has_one :photo
end

class Photo
  include Her::Model
end

...

[
    
{
        id: 1,
        name: "Something",
        photo: null
    },
    {
        id: 2,
        name: "Something else",
        photo: {
            id: 101,
            url: "http://example.com/image.png"
        }
    }
]

...

things = Thing.all()
things[1].photo.url # =>  "http://example.com/image.png"
things[0].photo.blank? # => false
things[0].photo.url # => NoMethodError: undefined method `empty?' for nil:NilClass