SWIG for C++, Symbol not found: Expected in: flat namespace

Question

I have a problem with loading the Python library I created by creating a Python API for a C++ project. When I load it into Python I get an error with Symbol not found:... Expected in: flat namespace...

EDIT: I have given the solution to my problem below.

Answer 1

When I have been looking around, it seemed that the problem most likely is due to linking with incompatible libraries. However, I have discovered that it actually was due to using an abstract class without an implementation code. That is, SWIG seems not be able to create a Python wrapper from a class declaration without implemented methods. I put it here so that anyone else having the same problem will find it. /Tomas