implicit conversion limitations

[Simone90]

Hi.

First problem.
I have two classes A and B.
I would like to have class B to be implicit convertible to A, but I would like not to expose the A(B) constructor in python, because I want to construct my object with factory methods only.
Can I achieve that in some ways?

Second problem.
I have a hierarchy.
A is the base class, B and C derives from A.
B and C are impl convertible from a string.
I have a container class with a method to add a vector of A.
I would like to make use of the implicit conversions of the subclasses of A:
I mean I would like to call the add with a vector which can contain not only instances of A, but also strings.
Can I do that?

Thanks for the help