How to use multiple arguments in \lstnewenvironment

Question

How can I have more than one optional argument to be passed to \lstnewenvironment?

I only need a fixed number of options and all will be present.

I want to pass the frame type and font size as arguments to my custom lstlisting.

Update

My current definition. I am currently passing the font size. I need frame type also (like single, leftline etc.)

\lstnewenvironment{pyout}[1][\tiny]{
    \lstset{ %
            basicstyle=\ttfamily#1\setstretch{1},
            showstringspaces=false,
            upquote=true,
            aboveskip=0pt,
            belowskip=2pt,
            breaklines=true,
            frame=leftline,
    }
}{}

Answer 1

You can add a new fontsize key:

\documentclass{article}

\usepackage{listings,setspace,textcomp}

\makeatletter
\newif\ifATOfontsize
\lst@Key{fontsize}{\tiny}{\def\ATOfontsize{#1}\global\ATOfontsizetrue}
\makeatother

\lstnewenvironment{pyout}[1][]{%
  \global\ATOfontsizefalse
  \lstset{%
    basicstyle=\ttfamily\tiny\setstretch{1},
    showstringspaces=false,
    upquote=true,
    aboveskip=0pt,
    belowskip=2pt,
    breaklines=true,
    frame=leftline,
    #1,
    }
  \ifATOfontsize
    \lstset{basicstyle=\ttfamily\ATOfontsize\setstretch{1}}
  \fi
  }{}

\begin{document}
\begin{pyout}[fontsize=\normalsize]
abc
\end{pyout}
\begin{pyout}[frame=single]
abc
\end{pyout}
\begin{pyout}[fontsize=\normalsize,frame=single]
abc
\end{pyout}
\end{document}

If the key is specified, a second \lstset command will be executed, for setting the font size.

In the following picture I've only reduced the text width.