remove python-can >=v4.0.0 as dependency

[VonSquiggles]

Bugs in python-can v4.0.0 break the API. Remove as dependency option until bugs are fixed.

[acolomb]

What bugs exactly are you talking about? What is it that breaks? Are these maybe fixed by now so we could upgrade the dependency to a known good version of python-can?

[VonSquiggles]

I don't recall the specific issues I was having, but Python-can v4 has several API changes, and the latest release on this repo is based on v3 API. There are plenty of known good versions of python-can v3 that you can use (looks like 3.3.4 is latest)

[acolomb]

I guess you are talking about the issues mentioned in #296? If there are others, could you please test again to pinpoint them?

Disallowing python-can >= 4.0.0 as a dependency is not a good option for the majority of the user-base. Since we only require >= 3.0.0, you can pin the last working version from that branch easily for your use-case, until the underlying bug in python-can (hardbyte/python-can#1285) is fixed. Thus I'd lean toward closing this PR.

[zariiii9003]

@VonSquiggles if you have problems with the Ixxat interface, a pull request in python-can would be helpful. The maintainers do not have access to the hardware.

Edit: It might have been fixed in hardbyte/python-can#1141

[fs570714]

@zariiii9003, @VonSquiggles
I use the Ixxat Interface with the canopen 2.1.0 and the python-can version 4.2.2 where the only issue I observed, occurred when using the network.sync.start() function.

File "XXX", line 55, in <module>
network.sync.start(0.010)
File "XXX\Python\Python311\Lib\site-packages\canopen\sync.py", line 38, in start
self._task = self.network.send_periodic(self.cob_id, [], self.period)
File "XXX\Programs\Python\Python311\Lib\site-packages\canopen\network.py", line 233, in send_periodic
return PeriodicMessageTask(can_id, data, period, self.bus, remote)<br/><br/>
File "XXX\Python\Python311\Lib\site-packages\canopen\network.py", line 315, in __init__
self._start()
File "XXX\Python\Python311\Lib\site-packages\canopen\network.py", line 318, in _start
self._task = self.bus.send_periodic(self.msg, self.period)
File "XXX\python-can-develop\can\bus.py", line 245, in send_periodic
periodic_tasks = self._periodic_tasks

AttributeError: 'IXXATBus' object has no attribute '_periodic_tasks'

however this issue is solved with the pull request hardbyte/python-can#1532