%%
%% The LaTeX Companion, 3ed
%%
%% Example 4-2-36 on page I-318 in "Defining your own variants".
%%
%% Copyright (C) 2022 Frank Mittelbach
%%
%% It may be distributed and/or modified under the conditions
%% of the LaTeX Project Public License, either version 1.3c
%% of this license or (at your option) any later version.
%%
%% See https://www.latex-project.org/lppl.txt for details.
%%

\documentclass{tlc3exa}
\pagestyle{empty}
\setcounter{page}{6}
\setlength\textwidth{135.0pt}

%StartShownPreambleCommands
\usepackage{fancyvrb}
\CustomVerbatimEnvironment{comment}{BVerbatim}{lastline=0}
%StopShownPreambleCommands

\begin{document}
A  simple way to implement a comment
\begin{comment}
  anything can go in here \begin{itemize} ...
\end{comment}
environment is shown in this example.
\end{document}