Given an entry, how to get all the fields passing a list of locales (ruby)

I’m sure is possible to do want I what to achieve but I’m not able to do it.
I’m using the ContentFul gem to connect my website with Contentful. I configured Contentful to support MultiLocale and now I’m able to add, for any fields, the content in the proper language. Indeed I’m not able to retrieve those contents at once.
In fact, if I do this
ContentfulModel::Base.client.entries({:content_type=>"myContentType", ""=>'myEntryId', 'locale'=> 'it-CH'})
It works perfectly and returns the contents in italian, the same happens with de-CH or fr-CH. Indeed it does not work with 'locale' = '*' which return only the default language instead of all them as stated by the documentation here

I’m obviously doing something wrong, but… what?
Thank you for the help!