I can’t upvote enough. If you’re writing a library or a plug-in that is going to work with different major versions of some containing application, you have to

I can’t upvote enough. If you’re writing a library or a plug-in that is going to work with different major versions of some containing application, you have to be somewhat flexible in what dependencies you require. You’re going to be coexisting with other plugins and libraries. If you want requests 2.23.0.1, and the other one wants 2.22, and the other one wants 2.24, all to simply do requests.get, madness follows from the people trying to use the library. This leads to either: forking, serial pip installs, or madness. Or all three. Libraries shouldn’t have a preference for tzinfo, or certifi. They certainly shouldn’t have conflicting preferences for them, and the only way that can happen is if the libraries defer to the application for the version of widely used core dependencies. There are exceptions, and generally fall along the lines of libraries that have tightly coupled dependencies, or cases where the specific advanced features are used. I’m thinking here of awscli and boto, but there have been epic disagreements on both between awscli and awsebcli.