code: @SuppressWarnings("unchecked")
      @Override
      public Boolean execute() {
          SmartFoxServer.getInstance()
                  .getAPIManager()
                  .getGameApi()
                  .sendInvitation(CommandUtil.getSfsUser(inviter, api), 
                          CommandUtil.getSFSUserList(invitees, api), 
                          expirySeconds, 
                          createCallback(), 
                          MapUtill.map2SFSObject(context, params));
          return Boolean.TRUE;
      }
docs: /* (non-Javadoc)
  @see com.tvd12.ezyfox.core.command.BaseCommand#execute()