尝试绘制一条线导致出现神秘的不匹配命令

Question

我需要在文档中绘制多行。由于我可能想要更改所有行的格式，所以我编写了一个新命令（这只是我第二次尝试编写自己的命令）。当我突出显示下面的整个 MWE 并在 WinEdit 中运行“编译选定”时，一切都正常。但是如果我运行 PDFTeXify，我会收到错误

！LaTeX 错误：\begin{flexlabelled} 在输入第 33 行以 \end{quote} 结尾。

我感到很困惑。

编辑：我尝试将 \quotesep 命令中的 [2] 更改为 [1]，但出现了同样的错误。

平均能量损失

\documentclass{memoir}
% \let\providelength\relax
\title{Interesting words}
\author{Peter Flom}
% \usepackage{hyperref}

\usepackage[marginpar]{todo}
\usepackage{url}
\usepackage{varioref}
\usepackage{ellipsis}

%% A convenience command, for typesetting the
%% word and pronunciation

%\newcommand{\entry}[2]{\medskip\noindent{\Large\textbf{#1} (#2)\par}}
\newcommand{\entry}[2]{\medskip\noindent{\Large\textbf{#1} \normalsize{#2} \par}}



%\newcommand{\sclabel}[1]{\normalfont\scshape #1}
\newcommand{\sclabel}[1]{\leavevmode{\normalfont\scshape #1}}
%% Less spacing around lists
\firmlists

%\newcommand{\quotesep}[1]{\rule{3in}{1pt}}
\newcommand{\quotesep}[2]{\rule{3in}{1pt}{\hfill}}

    \begin{document}
    
    
    
          \entry{Anonym[e]}{Pronunciation} %On Medium From Jones p. 271 other
             \begin{flexlabelled}{sclabel}{0pt}{0.5em}{0.5em}{*}{\leftmargin}
             \item[Definition]
             \textit{n.} A person who wishes to remain anonymous.
             \item[Etymology]
             Starting with Greek \textit{anonymous} through Latin and French.
             \item[Anti-thesaurus]\leavevmode
             \begin{description}
               \item[Incognita] -- which is a girl or woman who is unknown or disguised.
             \end{description}
             \item[Usage]
             We certainly need a word for this type of person! Everyone knows the word anonymous, but what about the person desiring anonymity?
             \item[Examples]  \leavevmode
               \epigraphwidth 3.5in
                 \epigraphrule 0pt
                  \epigraph{%
                      I should hardly risk a contest with all the anonymes \& synonymes of the Committee candidates.}{%
                \textit{Letter}\\ George Gordon Noel Byron}
               \quotesep
               \begin{quote} \hfill \\
                 Until relatively recently, many female science fiction authors were anonyms, believing that prejudice against women would hurt their sales if they used their true names.
               \end{quote}
             \item[Frequency]
             About 1 in 20 million words.
           \end{flexlabelled} \vspace{0.5in}
    
    \end{document}