code: public String get(Iterable<String> events, String defaultValue) {
          final Iterator<String> iter = getSeparate(events, defaultValue).iterator();
          StringBuilder builder = new StringBuilder();
          if (iter.hasNext()) {
              builder.append(iter.next());
              while (iter.hasNext()) {
                  builder.append(EVENT_LISTENER_DELIMITER);
                  builder.append(iter.next());
              }
          }
          return builder.toString();
      }
docs: Returns a space separated list of component IDs of components registered for at least one the `events`.
  
  @param events a collection of events
  @param defaultValue will be returned if no component is registered for one of the `events`
  @return a space separated list of fully qualified component IDs or `defaultValue`