_PyCode_ConstantKey() wraps a constant into a tuple that contains other items besides the wrapped object. This makes booleans different from 0 and 1, makes numbers of different type different (1, 1.0 and 1.0+0j), makes floating point zeros with different signs different (0.0 and -0.0), and avoids a ByteWarning from comparing strings and bytes.

But for some types objects are always different from objects of other types and from tuples. _PyCode_ConstantKey() can be made faster and using less memory if return the object of these types unwrapped.