add todo

Author: basnijholt

adaptive/tests/test_learners.py

@@ -30,6 +30,7 @@
 try:
     from adaptive.learner.skopt_learner import SKOptLearner
 except (ModuleNotFoundError, ImportError):
+    # XXX: catch the ImportError because of https://github.com/python-adaptive/adaptive/pull/278
     SKOptLearner = None