\begin{Verbatim}[commandchars=\\\{\}]
\PYG{k}{\PYGZbs{}xxx}\PYG{n+na}{[optional argument]}\PYG{n+nb}{\PYGZob{}}argument1\PYG{n+nb}{\PYGZcb{}\PYGZob{}}argument2\PYG{n+nb}{\PYGZcb{}}
\end{Verbatim}