Extension pattern in a flask controller using importlib 2.0

The first edition of the code can be found in this 1.0 version.

To summarize the problem :

• I have an endpoint in flask where the work logic change according to the query
• I am trying to implement an extension mechanism where the right class is loaded
• The first version did not provide caching of the imported class

Based on the answer from @netme, this is a code update where I lazy load the right handler class and cache it :

./run.py:

from flask import Flask, abort
import handler

app = Flask(__name__)

handler_collection = handler.HandlerCollection()

@app.route('/')
def api_endpoint():
    try:
        endpoint = "simple" # Custom logic to choose the right handler
        handler_instance = handler_collection.getInstance(endpoint)
    except handler.UnknownEndpoint as e:
        abort(404)

    print(handler_instance, handler_instance.name)
    # Handler processing. Not yet implemented

    return "Hello World"

if __name__ == "__main__":
    app.run(host='0.0.0.0', port=8080, debug=True)

./handler.py:

# -*- coding: utf-8 -*-
import importlib

import handlers

class UnknownEndpoint(Exception):
    pass

class HandlerCollection:
    _endpoints_classes = {}

    def addClass(self, endpoint_class):
        self._endpoints_classes[endpoint_class.name] = endpoint_class

    def getClass(self, endpoint_name):
        if (endpoint_name in self._endpoints_classes):
            return self._endpoints_classes.get(endpoint_name)

        try:
            # Try to import endpoint handler from a module in handlers package
            endpoint_module = importlib.import_module(
                '.{}'.format(str(endpoint_name)),
                'handlers')
            endpoint_module.register(self)
        except ImportError as e:
            raise UnknownEndpoint('Unknown endpoint \'{}\''.format(endpoint_name)) from e

        return self._endpoints_classes.get(endpoint_name)

    def getInstance(self, endpoint_name):
        endpoint_class = self.getClass(endpoint_name)
        return endpoint_class()

./handlers/simple.py:

# -*- coding: utf-8 -*-
class SimpleWebhookHandler:
    name = "simple"

def register(handler_collection):
    handler_collection.addClass(SimpleWebhookHandler)

Each handler needs to provide a register function which allows to have different handler class name and each handler class needs to provide a class attribute name.

Can you give me your opinion on this piece of code ? Is it "pythonic" ?