You’re right. “Side effect” here means that your program’s behavior changes simply by importing something, eg by monkey patching something else. If’s not: * I

You’re right. “Side effect” here means that your program’s behavior changes simply by importing something, eg by monkey patching something else. If’s not: * Importing other modules. * Taking a long time to import. * Writing .pyc files. If any program can “import foo” and still execute exactly the same bytecode afterward as before, you can say that foo doesn’t have side effects.