region.removeHalfspace(surface, side (+1, -1) ) seg faults

[GiudGiud]

When trying to modify a geometry manually (not a common use case), with the surface, and region containing the halfspace having been defined from Python, I get a seg fault. Posting the code below if someone has an idea of why. My guess is memory ownership issues.

`
/**

• @brief Removes a Node from this Region.
• @details //FIXME Does not handle complex CSG cells, only intersections
• @param surface the surface of Halfspace to remove
• @param halfspace the side of that surface
  /
  void Region::removeHalfspace(Surface surface, int halfspace) {

if (surface != NULL) {

std::vector<Region*>::iterator iter1;

/* Loop through nodes in region to check for the same Halfspace */
for ( ; iter1 != _nodes.end();) {

    if (dynamic_cast<Halfspace*>(*iter1)) {
      Halfspace* iter2 = dynamic_cast<Halfspace*>(*iter1);
      if (iter2->getSurface()->getId() == surface->getId() && 
          iter2->getHalfspace() == halfspace) {

        //delete iter2; FIXME Memory leak (seg faults with and without)
        _nodes.erase(iter1);
    }
  }
  else
    ++iter1;
}

}
}
`