public void createConditionalEdge(CFGVertice previousVertice, CFGVertice positiveTarget,
CFGVertice negativeTarget, Expression conditionOrNull) {
assertGraphVertice(previousVertice);
assertGraphVertice(positiveTarget);
assertGraphVertice(negativeTarget);
CFGMultiTargetEdge edge = new ConditionalEdge(previousVertice, positiveTarget, negativeTarget, conditionOrNull);
previousVertice.addEdge(edge);
edges.add(edge);
}