% -- I snipped this from the Python documentation distribution -- William Stein

% This sets up the {verbatim} environment to be indented and a minipage,
% and to have all the other mostly nice properties that we want for
% code samples.

\let\py@OldVerbatim=\verbatim
\let\py@OldEndVerbatim=\endverbatim
\RequirePackage{verbatim}
\RequirePackage{ifthen}

% Variable used by begin code command
\newlength{\py@codewidth}

\renewcommand{\verbatim}[1]{%
  \setlength{\parindent}{1cm}
  % Calculate the text width for the minipage:
  \setlength{\py@codewidth}{\linewidth}%
  \addtolength{\py@codewidth}{-\parindent}%
  %
\ifthenelse{\equal{#1}{}}{}{%
\begin{listing}[#1]\label{listing:#1}\index{code listing!#1}\mbox{}\vspace{-1.5em}\newline{}}%
\begin{list}{}{%
  \ifthenelse{\equal{#1}{}}{\setlength{\leftmargin}{4ex}}%
                           {\setlength{\leftmargin}{0ex}}}%
     \item%
     \py@OldVerbatim%
}
\renewcommand{\endverbatim}{%
    \py@OldEndVerbatim%
  \end{list}%
  %\end{listing}%
  \ifthenelse{\lengthtest{\leftmargin>2ex}}{\vspace{0.5em}}{------------------------------------------------------------------------\end{listing}}%
}