How can I include a listing inside a beamer in latex?

I'm using the listings package for Latex to insert a python code snippet inside a beamer. Here's the (although reduced to the bare minimum for the bug to happen) code :

\documentclass{beamer}
\usepackage{graphicx, listings, tikz, subcaption, amsmath} 
\usetheme{Copenhagen}
\setbeamertemplate{footline}[frame number]


\begin{document}

\maketitle

\begin{frame}{My frame}
    \begin{lstlisting}
        Why 
            doesn't 
        this work ??
    \end{lstlisting}
\end{frame}

\end{document}

The result is a compilation timeout, and I don't get why.

If your frame contains fragile content like listings, use the fragile frame option:

\documentclass{beamer}

\usepackage{
  %graphicx, 
  listings, 
  tikz, 
  subcaption, 
  %amsmath
} 
\usetheme{Copenhagen}
\setbeamertemplate{footline}[frame number]

\begin{document}

\maketitle

\begin{frame}[fragile]
  \frametitle{My frame}
    \begin{lstlisting}
Why 
    doesn't 
this work ??
    \end{lstlisting}
\end{frame}

\end{document}