> Are you sure your algorithm works well for expressions like exp(1/exp(1/(x-2)**2 - 1))? Or for general exp-log functions, as you assume in _has_only_supported_func?

I have added test for `_has_only_supported_func`, and hopefully it will work fine in more general cases too. I missed a case in `_has_only_supported_func` and it was making the tests fail. Do you know of any method other than strong tests to ensure that an algorithm works in general ?