I am creating a package with different internal functions that can be setup with the tokens provided during the initialization of the package. Inside the package, everything is written using the latex3 syntaxis.

I stumbled across a problem when evaluating a token using a "switch-case"-like command, specifically using the \tl\_case:NnTF. When calling my command \checkStyle I cannot manage to make it enter in the right case, the output in the document should be A, B, or C.

I suspect it is something very simple, but my low knowledge in latex3 does not allow me to find the source. I provide a minimal working example here below.

I hope you can help. Thanks in advance.

**typeset.sty**

```
\NeedsTeXFormat{LaTeX2e}[1994/06/01]
\ProvidesPackage{typeset}[2021/12/16 Typesetting Package]

% ------------------------  Load required packages
\RequirePackage{l3keys2e}

% ----------Trial
\ExplSyntaxOn

% Definition of the package options
\keys_define:nn { typeset }
{ 
% Create token list with opts
opt .tl_set:N = \l_typeset_opt_tl ,
deg .tl_set:N = \l_typeset_deg_tl ,
opt .initial:n = altern ,
deg .initial:n = other ,
}
\ExplSyntaxOff

% Process package options
\ExplSyntaxOn
\ProcessKeysOptions{ typeset }
\ExplSyntaxOff

% Create test case
\ExplSyntaxOn
\newcommand{ \test }
{
Content:~ \l_typeset_opt_tl ,  ~is~type~ \checkStyle{ \l_typeset_opt_tl }
\\
Content:~ \l_typeset_deg_tl , ~is~type~ \checkStyle{ \l_typeset_deg_tl } 
}
\ExplSyntaxOff 

% Token list switch-case 
\ExplSyntaxOn
\tl_new:N \l_mytoken_tl
\tl_const:Nn \c__altern_tl { altern }
\tl_const:Nn \c__nomin_tl { nomin }
\tl_const:Nn \c__other_tl { other }

\cs_new_protected:Npn \checkStyle #1 
{
    \tl_set:Nn \l_mytoken_tl { #1 }
    \tl_case:NnTF \l_mytoken_tl 
{
    \c__altern_tl {A}
    \c__nomin_tl {B}
    \c__other_tl {C}
}
  {}
  {None} 
  \\
  Input~to ~checkstyle~was: {#1}  
}
\ExplSyntaxOff

\endinput

```

**main.tex**

```
\documentclass{article}
\usepackage[opt=nomin]{typeset}

\begin{document}
\test
\end{document}

```

**Output:**

[![enter image description here](https://i.stack.imgur.com/yyN8y.png)](https://i.stack.imgur.com/yyN8y.png)