LaTeX Error: \begin{zentriert} on input line 54 ended by \end{document}

Question

i'm very new to latex and i'm trying to define a new environment that uses a existing environment and does some extra stuff at the beginning and the end. The environment i'm talking about is the "python" environment from the python package so i can highlight python code.

I defined my environment as the following:

\newenvironment{excall}
{\begin{python}}
{\end{python}}

and used it that way:

\begin{excall}
print("Hello")
print("1234")
\end{excall}

But getting this error:

! LaTeX Error: \begin{excall} on input line 54 ended by \end{document}.

if i try the same with the center environment instead of python, it works. What am i doing wrong?

Answer 1

The python environment from the python package is not for showing Python code, but for executing it.

Thus

\begin{python}
print("Hello")
print("1234")
\end{python}

will print

Hello 1234

If you want to highlight Python code, you can use the minted package. The igor style seems to choose the colors you like.

Beware that minted needs pdflatex to be run with the -shell-escape option.

\documentclass{article}
\usepackage{minted}

\usemintedstyle{igor}

\begin{document}

\begin{minted}{python}
print("Hello")
print("1234")
\end{minted}

\end{document}

You can customize minted, for instance

\documentclass{article}
\usepackage{minted}

\usepackage{lipsum} % for context

\usemintedstyle{igor}

\newenvironment{excall}
 {\VerbatimEnvironment\subsection*{Example call}\begin{minted}{python}}
 {\end{minted}\vspace{-\medskipamount}}

\begin{document}

\lipsum[4]

\begin{excall}
print("Hello")
print("1234")
\end{excall}

\lipsum[5]

\end{document}