Python Share Class Object among other processes

Question

I am creating Test Runner in Python that runs tests in parallel using multiprocess (fork of multiprocessing).

For now everything works fine, tests run well in this mode but the goal that I want to achieve right now is to being able to gather results in main (parent) process.

I have this Results class that I use to append particular TestCases:

class Results(object):

def __init__(self,
             status: Status = Status.PASS,
             message: str | None = None
             ) -> None:
    self.status = status
    self.message = message
    self.tests = []

def add(self, test: TestCase) -> None:
    """Add a Test to the list of tests."""
    if test.status is Status.FAIL:
        self.fail()

    self.tests.append(test)

def fail(self) -> None:
    """Indicate the test run had at least one failure."""
    self.status = Status.FAIL

I have created this ShareManager class like in here but sadly I can't really find any tests in my list after the execution. The self.results should be shared class variable in which I am appending test instances. I am sure that tests are running. What did I do wrong with this shared variable?

class ShareManager(BaseManager):
    pass

class MyProxy(NamespaceProxy):
    _exposed_ = ('__getattribute__', '__setattr__', '__delattr__', 'add')

def Manager():
    m = ShareManager()
    m.start()
    return m

ShareManager.register('Results', Results, MyProxy)


class Runner(object):
"""
Class responsible for creating processes in which
each test is executed separately and independently.
"""

def __init__(self) -> None:
    self.processes: list = []
    self.test_tree: list[dict] = create_tree()
    manager = Manager()
    self.results = manager.Results()

def run_tests(self) -> None:
    concurrency = 2
    semaphore = Semaphore(concurrency)
    start_time = get_time()

    # For each module in test hierarchy.
    for module in self.test_tree:
        module, mod_name, mod_members = self.importer(module)

        # For each TestSuite in module.
        for test_class in mod_members:
            _class = getattr(module, next(iter(test_class.keys())))

            # For each test in given TestSuite.
            for test_name in test_class[next(iter(test_class.keys()))]:
                _test_instance = _class(test_name)

                # HERE I TRY TO ADD TEST INSTANCES TO MY SHARED CLASS
                self.results.add(_test_instance)

                semaphore.acquire()

                process = S_Process(
                        target=getattr(_class, test_name),
                        args=(_test_instance,),
                        test_name=test_name,
                        start_time=start_time,
                        semaphore=semaphore,
                )
                process.start()
                self.processes.append(process)

    self.get_results()

def get_results(self) -> None:
    """
    Wait untill all processes are finished and get test results.
    """
    for process in self.processes:
        process.join()

    # SADLY, [] IS PRINTED HERE
    print(self.results.tests)