code: @SuppressWarnings("unchecked")
      public <T extends ElementBase> T getChild(Class<T> clazz, ElementBase last) {
          int i = last == null ? -1 : children.indexOf(last);
          
          for (i++; i < children.size(); i++) {
              if (clazz.isInstance(children.get(i))) {
                  return (T) children.get(i);
              }
          }
          
          return null;
      }
docs: Locates and returns a child that is an instance of the specified class. If none is found,
  returns null.
  
  @param <T> The type of child being sought.
  @param clazz Class of the child being sought.
  @param last If specified, the search begins after this child. If null, the search begins with
  the first child.
  @return The requested child or null if none found.