How to redefine section without error in tableofcontents

I noticed,what when i redefine section and use tableofcontents, I get an error:

! LaTeX Error: Something’s wrong–perhaps a missing item.

Help me please fix this problem. Thanks everybody very much for any help.

documentclass{article}
usepackage{tagpdf}
tagpdfsetup{tabsorder=structure,uncompress,activate-all,add-new-tag=Title/P,interwordspace=true}
ExplSyntaxOn
makeatletter
prop_gset_from_keyval:Nn{g__sections_prop}{chapter=H1,section=H2,subsection=H3,subsubsection=H4}
prop_map_inline:Nn g__sections_prop{
cs_set_eq:cc{orig@#1}{#1}
cs_gset_protected:cpn{#1}##1{
tagstructbegin{tag=#2}
tagmcbegin{tag=#2}
use:c{orig@#1}{##1x}
tagmcend
tagstructend
}
}
makeatother
ExplSyntaxOff
author{Alexandr Kozlovskiy}
title{test}
begin{document}
tagstructbegin{tag=Document}
tagstructbegin{tag=Title}
tagmcbegin{tag=Title}
maketitle
tableofcontents
tagmcend
tagstructend
section{test}
tagstructbegin{tag=P}
tagmcbegin{tag=P}
new test
tagmcend
tagstructend

section{new test}

tagstructbegin{tag=P}
tagmcbegin{tag=P}
new test again
tagmcend
tagstructend
tagstructend
end{document}