*
* @param {string} key
* @param {string} [prefix=wgCookiePrefix] The prefix of the key. If `prefix` is
* `undefined` or `null`, then `wgCookiePrefix` is used
* @param {Mixed} [defaultValue=null]
*
* @param {string} key
* @param {string} [prefix=wgCookiePrefix] The prefix of the key. If `prefix` is
* `undefined` or `null`, then `wgCookiePrefix` is used
* @param {Mixed} [defaultValue=null]