private boolean correctReachedSetFormatForProof(UnmodifiableReachedSet pReached) {
   if (pReached.getFirstState() == null
       || !(pReached.getFirstState() instanceof ARGState)
       || (extractLocation(pReached.getFirstState()) == null)) {
     logger.log(
         Level.SEVERE, "Proof cannot be generated because checked property not known to be true.");
     return false;
   }
   return true;
 }
 @Override
 public void constructInternalProofRepresentation(UnmodifiableReachedSet pReached) {
   if (correctReachedSetFormatForProof(pReached)) {
     root = (ARGState) pReached.getFirstState();
     stats.increaseProofSize(1);
   }
 }