Integers, floats, and booleans all work as expected.
Most string methods are implemented but, of the ones that are implemented, not all arguments are accepted. String formatting is limited, as is Unicode support.
Tuples must be a fixed length and list-to-tuple conversion is not handled in a general way, as there is no way for RPython to determine, non-statically, what the length of the result would be.
Lists are implemented as allocated arrays. Negative and out-of-bounds indexing is only allowed in limited cases. Obviously, fixed-length lists will optimize better, but appending to lists is relatively quick.
Dictionaries must have unique keys but custom hash functions or custom equality will be ignored.
Sets are not ...
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