add important comment to conftest

src/conftest.py

@@ -1,3 +1,11 @@
+# regarding conftest:
+# If you have conftest.py files which do not reside in a python package directory
+# (i.e. one containing an __init__.py) then “import conftest” can be ambiguous
+# because there might be other conftest.py files as well on your PYTHONPATH or
+# sys.path. It is thus good practise for projects to either put conftest.py under
+# a package scope or to never import anything from a conftest.py file.
+
+
 from pathlib import Path
 
 import pytest