iTextSharp.text.pdf.PdfDictionary.MergeDifferent C# (CSharp) Method

        public void MergeDifferent(PdfDictionary other)
        {
            foreach (PdfName key in other.hashMap.Keys) {
                if (!hashMap.ContainsKey(key)) {
                    hashMap[key] = other.hashMap[key];
                }
            }
        }

 protected PdfArray BranchForm(Dictionary<string,object> level, PdfIndirectReference parent, String fname) {
     PdfArray arr = new PdfArray();
     foreach (KeyValuePair<string,object> entry in level) {
         String name = entry.Key;
         Object obj = entry.Value;
         PdfIndirectReference ind = PdfIndirectReference;
         PdfDictionary dic = new PdfDictionary();
         if (parent != null)
             dic.Put(PdfName.PARENT, parent);
         dic.Put(PdfName.T, new PdfString(name, PdfObject.TEXT_UNICODE));
         String fname2 = fname + "." + name;
         int coidx = calculationOrder.IndexOf(fname2);
         if (coidx >= 0)
             calculationOrderRefs[coidx] = ind;
         if (obj is Dictionary<string,object>) {
             dic.Put(PdfName.KIDS, BranchForm((Dictionary<string,object>)obj, ind, fname2));
             arr.Add(ind);
             AddToBody(dic, ind);
         }
         else {
             List<object> list = (List<object>)obj;
             dic.MergeDifferent((PdfDictionary)list[0]);
             if (list.Count == 3) {
                 dic.MergeDifferent((PdfDictionary)list[2]);
                 int page = (int)list[1];
                 PdfDictionary pageDic = pageDics[page - 1];
                 PdfArray annots = pageDic.GetAsArray(PdfName.ANNOTS);
                 if (annots == null) {
                     annots = new PdfArray();
                     pageDic.Put(PdfName.ANNOTS, annots);
                 }
                 PdfNumber nn = (PdfNumber)dic.Get(iTextTag);
                 dic.Remove(iTextTag);
                 AdjustTabOrder(annots, ind, nn);
             }
             else {
                 PdfArray kids = new PdfArray();
                 for (int k = 1; k < list.Count; k += 2) {
                     int page = (int)list[k];
                     PdfDictionary pageDic = pageDics[page - 1];
                     PdfArray annots = pageDic.GetAsArray(PdfName.ANNOTS);
                     if (annots == null) {
                         annots = new PdfArray();
                         pageDic.Put(PdfName.ANNOTS, annots);
                     }
                     PdfDictionary widget = new PdfDictionary();
                     widget.Merge((PdfDictionary)list[k + 1]);
                     widget.Put(PdfName.PARENT, ind);
                     PdfNumber nn = (PdfNumber)widget.Get(iTextTag);
                     widget.Remove(iTextTag);
                     PdfIndirectReference wref = AddToBody(widget).IndirectReference;
                     AdjustTabOrder(annots, wref, nn);
                     kids.Add(wref);
                     Propagate(widget, null, false);
                 }
                 dic.Put(PdfName.KIDS, kids);
             }
             arr.Add(ind);
             AddToBody(dic, ind);
             Propagate(dic, null, false);
         }
     }
     return arr;
 }