Hi Martin, to expand on my previous comments: the template for _Driver already exists; I'm suggesting to make it public. Consequently, StorageHelper should accept a driver parameter to __init__ , defaulting to None . Only when its value is not provided by the user should the library go out of its way to do the right thing and check all the known storage providers, fetch credentials, what not - stuff that will not work for most users, most of the time (even if you put in an inordinate amount of effort, you'll still not be able to match whatever version of, say, azure-blob-storage the user happens to have installed, or to fetch the credentials correctly in every setting - e.g. when the user uses managed identity).