code: function(ownerId, userId, callback) {
        if (!ownerId) return callback(new Error(utils.i18n.blocklist.ownerId));
        if (!userId) return callback(new Error(utils.i18n.blocklist.userId));
        utils.debug('Blocklist block: ' + ownerId + ' userId: ' + userId);
  
        request.post({
          path: '/users/' + querystring.escape(ownerId) + '/blocks',
          body: {
            user_id: userId
          }
        }, callback || utils.nop);
      }
docs: Block a single user
  
  @param  {String}   ownerId  Owner ID of the block list
  @param  {String}   userId   User being blocked
  @param  {Function} callback Callback function