code: public static SimpleMDAGNode traverseMDAG(SimpleMDAGNode[] mdagDataArray, SimpleMDAGNode sourceNode, String str)
      {
  //        char firstLetter = str.charAt(0);
  
          //Loop through the SimpleMDAGNodes in the processing MDAG's source node's _transition set,
          //searching for the the one with a letter (char) equal to the first char of str.
          //We can use that target node to _transition through the MDAG with the rest of the string
          return sourceNode.transition(mdagDataArray, str.toCharArray());
  //        for(int i = 0; i < sourceNode.transitionSetSize; i++)
  //        {
  //            if(mdagDataArray[i].getLetter() == firstLetter)
  //                return mdagDataArray[i]._transition(mdagDataArray, str.substring(1));
  //        }
  //        /////
  //
  //        return null;
      }
docs: Follows a _transition path starting from the source node of a MDAG.
  
  @param mdagDataArray the array containing the data of the MDAG to be traversed
  @param sourceNode    the dummy SimpleMDAGNode which functions as the source of the MDAG data in {@code mdagDataArray}
  @param str           a String corresponding to a _transition path in the to-be-traversed MDAG
  @return the SimpleMDAGNode at the end of the _transition path corresponding to
  {@code str}, or null if such a _transition path is not present in the MDAG