docs: function parse_theme_xml(data, opts) {
  	/* 20.1.6.9 theme CT_OfficeStyleSheet */
  	if(!data || data.length === 0) return parse_theme_xml(write_theme());
  
  	var t;
  	var themes = {};
  
  	/* themeElements CT_BaseStyles */
  	if(!(t=data.match(themeltregex))) throw new Error('themeElements not found in theme');
  	parse_themeElements(t[0], themes, opts);
  
  	return themes;
  }