/// <summary>
 /// Accepts evaluating visitor.
 /// </summary>
 /// <param name="visitor">Evaluating visitor.</param>
 /// <param name="state">Reference state.</param>
 /// <returns>List of successors.</returns>
 public IEnumerable <ISuccessor> Accept(IOperatorDecisionTreeApplicabilityVisitor visitor, IState state)
 {
     return(visitor.Visit(this, state));
 }
 /// <summary>
 /// Accepts evaluating visitor.
 /// </summary>
 /// <param name="visitor">Evaluating visitor.</param>
 /// <param name="state">Reference state.</param>
 /// <returns>List of successors.</returns>
 public IEnumerable <ISuccessor> Accept(IOperatorDecisionTreeApplicabilityVisitor visitor, IState state)
 {
     yield break;
 }