.bool_set_inverse:N 的使用似乎与其定义不符

Question

这是一个 mwe

\documentclass{article}

\ExplSyntaxOn

\cs_new:Nn \en_direct: { beginning }

\keys_define:nn { test }
{
  direct .bool_set:N = \test_direct_bool,
  indirect .bool_set_inverse:N = \test_direct_bool,
  direct .initial:n = {true},
  direct .default:n = {true},
  direct .code:n = {
    \bool_if:nTF {\test_direct_bool}
    {\cs_set:Nn \en_direct: { DIRECT }}
    {\cs_set:Nn \en_direct: { INDIRECT }}
  }, 
  indirect .initial:n = {false},
  indirect .default:n = {true},
  indirect .code:n = {
    \bool_if:nTF {\test_direct_bool}
    {\cs_set:Nn \en_direct: { DIRECT }}
    {\cs_set:Nn \en_direct: { INDIRECT }}
  }
}

\NewDocumentCommand{\seekey}{ m }{
  \bool_if:nTF {\use:c{test_#1_bool}} {key~#1~is~true} {key~#1~is~false}
  \qquad [\en_direct:]\par\noindent\hrulefill\par
}

\NewDocumentCommand{\valuekey}{m}
{
  \keys_set:nn { test }{ #1 } The~key~\textbf{#1}~has~been~set~to~TRUE.\par
}

\ExplSyntaxOff

\begin{document}

\seekey{direct}

\valuekey{direct} \seekey{direct}

\valuekey{indirect} \seekey{direct}

\end{document}

我期望最后一位给出“key direct is false”和“INDIRECT”作为值，\en_direct: 但事实并非如此。

我对以下 expl3 文档中的内容有什么遗漏或误解：

key .bool_set_inverse:N = boolean

定义key为设置boolean为的逻辑逆value（必须为真或假）。