Listing all instance of a class

Question

I wrote a Python module, with several classes that inherit from a single class called MasterBlock. I want to import this module in a script, create several instance

Answer 1

What about adding a class variable, that contains all the instances of MasterBlock? You can record them with:

Class MasterBlock(object):

    all_instances = []  # All instances of MasterBlock

    def __init__(self,…):
        …
        self.all_instances.append(self)  # Not added if an exception is raised before

You get all the instances of MasterBlock with MasterBlock.all_instances (or instance.all_instances).

This works if all base classes call the __init__ of the master class (either implicitly through inheritance or explicitly through the usual super() call).