Using xsim for creating tex files for Question Banks

Question

I have been able to use xsim to extract easy, medium and difficult questions from a tagged Question Bank. However, I am not able to get the tex file with the list of all easy questions, all medium questions and all difficult questions.

Here is a MWE:

\documentclass[14pt]{article}
\usepackage{amsmath, amssymb, amsthm, amsfonts}
\usepackage[verbose,clear-aux]{xsim}
\usepackage{filecontents}

\DeclareExerciseCollection{foo-easy}
\DeclareExerciseCollection{foo-medium}
\DeclareExerciseCollection{foo-difficult}
\DeclareExerciseTagging{difficulty}
\xsimsetup
{
    difficulty={1,2,3},
    print-collection/print=both
}
\begin{filecontents*}
    {foo.tex}

    \begin{exercise}[difficulty=1]
        bla bla
\end{exercise}
\begin{solution}
bla bla bla
\end{solution}

\begin{exercise}[difficulty = 2]
bla
\end{exercise}
\begin{solution}
bla bla bla bla
\end{solution}
\end{filecontents*}

\begin{document}
\collectexercises{foo-easy}
\xsimsetup{difficulty=1}
\input{foo.tex}
\collectexercisesstop{foo-easy}

\collectexercises{foo-medium}
\xsimsetup{difficulty=2}
\input{foo.tex}
\collectexercisesstop{foo-medium}

\collectexercises{foo-difficult}
\xsimsetup{difficulty=3}
\input{foo.tex}
\collectexercisesstop{foo-difficult}

\section{Level 01 Problems}
\printcollection{foo-easy}
\printsolutionstype*{foo-easy}

\section{Level 02 Problems}
\printcollection{foo-medium}

\section{Level 03 Problems}
\printcollection{foo-difficult}

\end{document}