public PassageMacroBranchNode(MacroBranchType branchType)
     : base(PassageContent.ContentType.BranchContent)
 {
     if (branchType != MacroBranchType.Else)
     {
         throw new Exception("Only a else branch have no expression");
     }
     _branchType = branchType;
 }
 public PassageMacroBranchNode(MacroBranchType branchType, Expression expression)
     : base (PassageContent.ContentType.BranchContent)
 {
     _branchType = branchType;
     _expression = expression;
 }