This is a possibly silly question, but looking at the mapping of operators to functions I noticed that there is no function to express the not in
operator. At
Another function is not necessary here. not in
is the inverse of in
, so you have the following mappings:
obj in seq => contains(seq, obj)
obj not in seq => not contains(seq, obj)
You are right this is not consistent with is
/is not
, since identity tests should be symmetrical. This might be a design artifact.