HTML_Common2 | --HTML_QuickForm2_Element_Select_OptionContainer | --HTML_QuickForm2_Element_Select_Optgroup
Do not instantiate this class yourself, use HTML_QuickForm2_Element_Select::addOptgroup() method
HTML_QuickForm2_Element_Select_Optgroup __construct( array &$values, array &$possibleValues, string $label, [string|array $attributes = null])
void __toString( )