Contains the names of built-in modules which can be safely imported.
The value for \class{RExec} is \code{('audioop', 'array', 'binascii',
'cmath', 'errno', 'imageop', 'marshal', 'math', 'md5', 'operator',
-'parser', 'regex', 'rotor', 'select', 'sha', '_sre', 'strop',
+'parser', 'regex', 'select', 'sha', '_sre', 'strop',
'struct', 'time')}. A similar remark about overriding this variable
applies --- use the value from the base class as a starting point.
\end{memberdesc}