docstring const & preamble() const { return preamble_; }
///
docstring const & htmlpreamble() const { return htmlpreamble_; }
///
docstring const & htmlstyles() const { return htmlstyles_; }
/// Looks for the layout of "highest level", other than Part (or other
docstring const & preamble() const { return preamble_; }
///
docstring const & htmlpreamble() const { return htmlpreamble_; }
///
docstring const & htmlstyles() const { return htmlstyles_; }
/// Looks for the layout of "highest level", other than Part (or other