Unable to send periodic messages with IXXAT interface as of 4.0.0.

### Description:
While attempting to set up a periodic task to synchronously write/read PDOs using an IXXAT USB-to-CAN and the [canopen](https://github.com/christiansandberg/canopen) package, an AttributeError is generated due to the `IXXATBus` object missing `_periodic_tasks` (see: traceback below).

_Update:_ After digging around with pdb, it looks like there's some additional wrapping applied to the `IXXATBus` object - storing the actual `bus` object in its own attribute (`self.bus`) rather than returning the bus object itself to the caller of `interface.Bus.__new__`. If the bus object held by the canopen library's `network` object is replaced with the `bus` object inside the `bus` object returned from `interface.Bus.__new__`, then there is no issue as the `_periodic_tasks` array is initialised correctly in that inner `bus` object:

_e.g._

```
import canopen
net = canopen.Network()
net.bus = net.bus.bus
print(len(net.bus._periodic_tasks))
```

Runs without error. **But**, there should be no need to unwrap the inner `bus` object in this way.

### Expected behavior
On v3.3.4, it is possible to use `node.rpdo[pdo].start` or `network.sync.start` from the `canopen` package (on its latest 2.0.0 release) without any errors being generated. Calling the constructor does not resolve the issue on V4.0.0, however, manually setting `bus._periodic_tasks = []` functions as a workaround.

The `bus` object returned by `interface.Bus.__new__` on V3.3.4 contains an empty `_periodic_tasks` array. On V4.0.0, the user must access `bus.bus` in order to access it.

### Additional context

OS and version: Windows 10 Professional (10.0.19044 Build 19044)
Python version: Python 3.9.10, also confirmed with Python 3.10.3
python-can version: 4.0.0
python-can interface/s (if applicable): IXXAT.

Traceback and logs

```

Traceback (most recent call last):
line 78, in
main()
line 54, in main
network.start_nodes(net, 0.5)
start_nodes
node.rpdo[pdo].start(sync_time)
line 449, in start
self._task = self.pdo_node.network.send_periodic(
"...\canopen\network.py", line 220, in send_periodic
return PeriodicMessageTask(can_id, data, period, self.bus, remote)
"...\canopen\network.py", line 294, in __init__
self._start()
"...\canopen\network.py", line 297, in _start
self._task = self.bus.send_periodic(self.msg, self.period)
"...\python_can\can\bus.py", line 239, in send_periodic
periodic_tasks = self._periodic_tasks
AttributeError: 'IXXATBus' object has no attribute '_periodic_tasks'
```

Bus attributes on 4.0.0:
['RECV_LOGGING_LEVEL', '__abstractmethods__', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__enter__', '__eq__', '__exit__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_abc_impl', '_apply_filters', '_detect_available_configs', '_matches_filters', '_recv_internal', '_send_periodic_internal', **'bus'**, 'channel_info', 'fileno', 'filters', 'flush_tx_buffer', 'recv', 'send', 'send_periodic', 'set_filters', 'shutdown', 'state', 'stop_all_periodic_tasks']

Bus attributes on 3.3.4:
['CHANNEL_BITRATES', 'RECV_LOGGING_LEVEL', '_IXXATBus__set_filters_has_been_called', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__enter__', '__eq__', '__exit__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__iter__', '__le__', '__lt__', '__metaclass__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', '_apply_filters', '_channel_capabilities', '_channel_handle', '_control_handle', '_detect_available_configs', '_device_handle', '_device_info', '_inWaiting', '_matches_filters', '_message', '_payload', '_periodic_tasks', '_receive_own_messages', '_recv_internal', '_scheduler', '_scheduler_resolution', '_send_periodic_internal', '_tick_resolution', 'channel', 'channel_info', 'filters', 'flush_tx_buffer', 'recv', 'send', 'send_periodic', 'set_filters', 'shutdown', 'state', 'stop_all_periodic_tasks']