Numbering exceeding the 26 letter alphabet

Question

After reading this answer https://tex.stackexchange.com/a/52604/10898 I am unable to employ the alphalph package to replace the counter in either levels. See the code below:

\documentclass[letterpaper]{article}
\usepackage{alphalph} % unable to use this package based on the answer given.
\usepackage{enumitem}
\setlist[enumerate,1]{label=(\roman*)}
\setlist[enumerate,2]{label=(\alph*)}
\begin{document}
\begin{enumerate}
\item 
    \begin{enumerate}
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item 
    \item
    \item 
    \item 
    \item 
    \item
    \item 
    \item 
    \item 
    \end{enumerate}
\end{enumerate}
\end{document}

I have made the proper replacement but get no results:

\makeatletter
\newalphalph{\alphmult}[mult]{\@alph}{26}
\makeatother
\renewcommand{\theenumi}{\alphmult{\value{enumi}}}

Answer 1

I answered the same question here. The documentation of enumitem has an extra section about counters. It's section 8.1 New counter representation

\documentclass[]{article}
\usepackage{alphalph}
\usepackage{enumitem}

\makeatletter
\def\enumalphalphcnt#1{\expandafter\@enumalphalphcnt\csname c@#1\endcsname}
\def\@enumalphalphcnt#1{\alphalph{#1}}
\makeatother
\AddEnumerateCounter{\enumalphalphcnt}{\@enumalphalphcnt}{aa}
\setenumerate{label=\arabic*}
\setenumerate[2]{label=\enumalphalphcnt*)}
\begin{document}
\begin{enumerate}
\item foo
\item bar
\item next level
\begin{enumerate}
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\item foo \item bar \item foo
\item bar \item foo \item bar
\end{enumerate}
\end{enumerate}
\end{document}