"sebastien.lannez@gmail.com" <sebastien.lannez@gmail.com> writes:

> I need to overload the operator in and let him return an object
> ... It seems it is not a behavior Python expect :

Python expects it all right, but it intentionally converts the value
to a boolean. The 'in' operator calls PySequence_Contains, which
returns a boolean value at the C level. User-supplied __contains__ is
implemented as an adaptor in typeobject.c (slot_sq_contains). It
takes the value returned by your __contains__ implementation and
converts it to 0 or 1.

I don't think you can overload 'in' as you want without pervasive
changes to CPython source code.