Check issue with pandas version

[florian-huber]

Currently we have pandas==1.2.5 which seems a too strict requirement to me.
Let's check if we can change that.

[florian-huber]

I started looking into this in #105.
Seems using pandas>=1.2.5 causes issues due to the way set() is used here...

[florian-huber]

The tests now pass with higher pandas versions. @niekdejonge do you know any other issues that were caused by pandas not equal to 1.2.5 ?

[niekdejonge]

That is really nice. The original problem with pandas was different. Loading pickled files that are made in older pandas version could not be loaded giving the vague error: E TypeError: cinit() takes at least 2 positional arguments (0 given). A discussion about this issue can be found here: pandas-dev/pandas#42345. This gave a problem for every test that relied on previously created pickled test files.

So I actually think a new release of pandas (or pickle) must have solved the original problem. So the pandas version can be changed, solving the problem. Might still be good to choose a different method than pickling, to prevent future similar issues. see #67

[florian-huber]

OK, thanks!
In the issue you mention there also someone reporting that changing pickle.load to pandas.read_pickle helped. Maybe that could be added to our utils as well.