UTF-8 Mu won't render inside custom environment

Question

I just tried using this https://tex.stackexchange.com/a/83883/143861 for syntax highlighting Python in overleaf

\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}

% Default fixed font does not support bold face
\DeclareFixedFont{\ttb}{T1}{txtt}{bx}{n}{12} % for bold
\DeclareFixedFont{\ttm}{T1}{txtt}{m}{n}{12}  % for normal

% Custom colors
\usepackage{color}
\definecolor{deepblue}{rgb}{0,0,0.5}
\definecolor{deepred}{rgb}{0.6,0,0}
\definecolor{deepgreen}{rgb}{0,0.5,0}

\usepackage{listings}

% Python style for highlighting
\newcommand\pythonstyle{\lstset{
language=Python,
basicstyle=\ttm,
morekeywords={self},              % Add keywords here
keywordstyle=\ttb\color{deepblue},
emph={MyClass,__init__},          % Custom highlighting
emphstyle=\ttb\color{deepred},    % Custom highlighting style
stringstyle=\color{deepgreen},
frame=tb,                         % Any extra options here
showstringspaces=false
}}


% Python environment
\lstnewenvironment{python}[1][]
{
\pythonstyle
\lstset{#1}
}
{}

% Python for external files
\newcommand\pythonexternal[2][]{{
\pythonstyle
\lstinputlisting[#1]{#2}}}

% Python for inline
\newcommand\pythoninline[1]{{\pythonstyle\lstinline!#1!}}

A Mu µ in the Python environment won't render

\begin{document}
\begin{python}
µ = 5
\end{python}
\end{document}

Due to this error:

Package inputenc Error: Invalid UTF-8 byte "B5.

It renders outside of the python environment.

How can I render a mu inside of a syntax-highlighted Python code block?

Answer 1

You need to declare the character to listings.

I suggest also to use newtxtt that has better symbol coverage than txtt.

\documentclass[a4paper,12pt]{article}
\usepackage[utf8]{inputenc}
\usepackage{newtxtt}

% Custom colors
\usepackage{color}
\definecolor{deepblue}{rgb}{0,0,0.5}
\definecolor{deepred}{rgb}{0.6,0,0}
\definecolor{deepgreen}{rgb}{0,0.5,0}

\usepackage{listings}

% Python style for highlighting
\newcommand\pythonstyle{%
  \lstset{
    language=Python,
    basicstyle=\ttfamily,
    morekeywords={self},              % Add keywords here
    keywordstyle=\bfseries\color{deepblue},
    emph={MyClass,__init__},          % Custom highlighting
    emphstyle=\bfseries\color{deepred},    % Custom highlighting style
    stringstyle=\color{deepgreen},
    frame=tb,                         % Any extra options here
    showstringspaces=false,
  }%
}

\lstset{literate={µ}{\textmu}{1}}


% Python environment
\lstnewenvironment{python}[1][]
  {\pythonstyle\lstset{#1}}
  {}

% Python for external files
\newcommand\pythonexternal[2][]{{%
  \pythonstyle
  \lstinputlisting[#1]{#2}%
}}

% Python for inline
\newcommand\pythoninline[1]{{\pythonstyle\lstinline!#1!}}

\begin{document}
\begin{python}
µ = 5
for f
\end{python}
\end{document}

The picture shows that there is a distinctive bold font.