public Tuple<Collection<BasicOperator>, Collection<BasicOperator>> transformOperatorGraph(
final Map<String, BasicOperator> mso,
final BasicOperator rootOperator) {
final Collection<BasicOperator> deleted = new LinkedList<BasicOperator>();
final Collection<BasicOperator> added = new LinkedList<BasicOperator>();
final ReplaceVar replaceVar = (ReplaceVar) mso.get("replaceVar");
final LinkedList<BasicOperator> pres = (LinkedList<BasicOperator>) replaceVar
.getPrecedingOperators();
final LinkedList<OperatorIDTuple> succs = (LinkedList<OperatorIDTuple>) replaceVar
.getSucceedingOperators();
BasicOperator pre;
OperatorIDTuple idTuple;
// Connect all precessors to all successors