public function open(ModelForm $form, $attributes = [])
{
if ($this->containers) {
throw new \RuntimeException('Prior call to close() is required');
}
if (is_string($attributes)) {
$attributes = $this->parseAttributes($attributes);
}
foreach ($attributes as $attribute => $value) {
$form->setAttribute($attribute, $value);
}
$this->containers[] = $form;
return '<form' . $this->implodeAttributes($form->getAttributes()) . ">\n";
}
