Merge branch 'AM_functorcollections' into 'master'

Instantiation of FunctorCollection() with empty dictionary

See merge request lhcb/DaVinci!664

DaVinciExamples/python/DaVinciExamples/tupling/option_davinci_tupling_from_collections.py

@@ -37,7 +37,7 @@ assert len(collections) == len(
     functorcollections.
     __all__), "Oh no! Did you forget to add a new collection to this test?"
 
-variable_collection = FunctorCollection({})
+variable_collection = FunctorCollection()
 for coll in collections:
     variable_collection += coll