# Enumeration embedded in an enumeration in a special way

I am trying to embed an enumerate environment into another one. Everything is fine if I do add not the content between [] after the second begin{enumerate}. If I do add that, there is a problem: I get a series of ? as the first line. Anyone, that understand how to fix this problem?

Here is the code:

\documentclass[11pt,twoside,letterpaper]{article}
\usepackage{enumerate}
\begin{document}
\begin{enumerate}[label={(\textbf{Point 1})}, ref={(Point 1)}, leftmargin=2cm]
\item
\begin{enumerate}[label={(P\arabic*)},\ref={(P\arabic*)}]
\item 1
\item 2
\end{enumerate}
\end{enumerate}
\end{document}


There are two errors:

you should use enumitem instead of enumerate and in the second [] you have a \ref instead of ref.

So the correct example should be:

\documentclass[11pt,twoside,letterpaper]{article}
\usepackage{enumitem}
\begin{document}
\begin{enumerate}[label={(\textbf{Point 1})}, ref={(Point 1)}, leftmargin=2cm]
\item
\begin{enumerate}[label={(P\arabic*)}, ref={(P\arabic*)}]
\item 1
\item 2
\end{enumerate}
\end{enumerate}
\end{document}


You should use \usepackage{enumitem} and not \usepackage{enumerate}.