Add explanatory comment about -I flag

makefile

@@ -9,6 +9,9 @@ type-check:
 	@mypy .
 
 test:
+    # We add the `-I` flag to only use the installed package and not use local modules.
+    # Note that we cannot add it to all tests because of the implemented import logic.
+    # See PR #49 for more details.
 	@python3 -I -m unittest discover -s tests/ -p "*_test.py"
 	@python3 -I -m unittest discover -s distributed_shampoo/tests/ -p "*_test.py"
 	@python3 -m unittest discover -s distributed_shampoo/utils/tests/ -p "*_test.py"