docs: private AlphaNode getFirstAlphaNode(final ObjectHashMap hashedAlphaNodes) throws IllegalArgumentException {
          AlphaNode firstAlphaNode;
  
          final Iterator iter = hashedAlphaNodes.iterator();
          final ObjectHashMap.ObjectEntry entry = (ObjectHashMap.ObjectEntry) iter.next();
  
          if (entry != null) {
              firstAlphaNode = (AlphaNode) entry.getValue();
          } else {
              throw new IllegalArgumentException("ObjectHashMap does not contain any hashed AlphaNodes!");
          }
  
          return firstAlphaNode;
      }