\LoadClass[11pt,a4paper,twoside]{book}

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\RequirePackage{amsmath}
\RequirePackage{amsthm}
\RequirePackage{amssymb}
\RequirePackage{mathrsfs}
\RequirePackage{float}

%%%%%%%%%%%%%%%%%%%%%
\RequirePackage{xepersian}
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\theoremstyle{definition}
\newtheorem{definition}{تعریف}[chapter]
\newtheorem{ques}[definition]{}
\theoremstyle{definition}
\renewcommand{\qedsymbol}{$ \blacksquare $}
\renewcommand{\proofname}{\rm \bfseries حل}
\newenvironment{solo}
{\begin{proof}}
{\end{proof}}


\begin{document}
\begin{solo}
این حل یک سؤال است.
\end{solo}

\begin{proof}
این اثبات یک قضیه است
\end{proof}
\end{document}