Config flow could not be loaded: {"message":"Invalid handler specified"}

[ArturZurawski]

When adding integration I got

Config flow could not be loaded: {"message":"Invalid handler specified"}

ha: 2024.12.1

it works with ha: 2024.11.3

When installed on 2024.11.3 and migrated to 2024.12.1 got this error:

Logger: homeassistant.setup
Source: setup.py:334
First occurred: 10:37:37 PM (1 occurrences)
Last logged: 10:37:37 PM

Setup failed for custom integration 'luxtronik2': Unable to import component: No module named 'luxtronik'
Traceback (most recent call last):
  File "/usr/src/homeassistant/homeassistant/setup.py", line 334, in _async_setup_component
    component = await integration.async_get_component()
                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1034, in async_get_component
    self._component_future.result()
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1014, in async_get_component
    comp = await self.hass.async_add_import_executor_job(
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
        self._get_component, True
        ^^^^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/usr/local/lib/python3.13/concurrent/futures/thread.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File "/usr/src/homeassistant/homeassistant/loader.py", line 1074, in _get_component
    ComponentProtocol, importlib.import_module(self.pkg_path)
                       ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^
  File "/usr/src/homeassistant/homeassistant/util/loop.py", line 200, in protected_loop_func
    return func(*args, **kwargs)
  File "/usr/local/lib/python3.13/importlib/__init__.py", line 88, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 1022, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/config/custom_components/luxtronik2/__init__.py", line 28, in <module>
    from .coordinator import LuxtronikCoordinator
  File "/config/custom_components/luxtronik2/coordinator.py", line 22, in <module>
    from .common import correct_key_value
  File "/config/custom_components/luxtronik2/common.py", line 25, in <module>
    from .model import LuxtronikCoordinatorData
  File "/config/custom_components/luxtronik2/model.py", line 10, in <module>
    from luxtronik import Calculations, Parameters, Visibilities
ModuleNotFoundError: No module named 'luxtronik'