protected function _singleDatetime($options, $keep)
{
$off = array_diff($this->_datetimeParts, [$keep]);
$off = array_combine($off, array_fill(0, count($off), false));
$attributes = array_diff_key($options, array_flip(array_merge($this->_datetimeOptions, ['value', 'empty'])));
$options = $options + $off + [$keep => $attributes];
if (isset($options['value'])) {
$options['val'] = $options['value'];
}
return $options;
}