code: def createReader(clazz, readername):
          
          if not clazz in ReaderFactory.factories:
              ReaderFactory.factories[clazz] = get_class(clazz).Factory()
          return ReaderFactory.factories[clazz].create(readername)
docs: Static method to create a reader from a reader clazz.
  
          @param clazz:      the reader class name
          @param readername: the reader name