#!/usr/bin/env python3

import pykka


class PlainActor(pykka.ThreadingActor):
    def __init__(self):
        super().__init__()
        self.stored_messages = []

    def on_receive(self, message):
        if message.get('command') == 'get_messages':
            return self.stored_messages
        else:
            self.stored_messages.append(message)


if __name__ == '__main__':
    actor = PlainActor.start()
    actor.tell({'no': 'Norway', 'se': 'Sweden'})
    actor.tell({'a': 3, 'b': 4, 'c': 5})
    print(actor.ask({'command': 'get_messages'}))
    actor.stop()

#!/usr/bin/env python3

import pykka


GetMessages = object()


class PlainActor(pykka.ThreadingActor):
    def __init__(self):
        super().__init__()
        self.stored_messages = []

    def on_receive(self, message):
        if message is GetMessages:
            return self.stored_messages
        else:
            self.stored_messages.append(message)


if __name__ == '__main__':
    actor = PlainActor.start()
    actor.tell({'no': 'Norway', 'se': 'Sweden'})
    actor.tell({'a': 3, 'b': 4, 'c': 5})
    print(actor.ask(GetMessages))
    actor.stop()

Use custom message instead of dict