Dispatch event programmatically

Development
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1

###Magento 1.x code:

Mage::dispatchEvent($eventName, $data);

###Magento 2 code:

/**
 * @param string $eventName
 * @param array(string => mixed) $data
 * @return void
 */
function df_dispatch($eventName, array $data = []) {
	/** @var \Magento\Framework\ObjectManagerInterface $om */
	$om = \Magento\Framework\App\ObjectManager::getInstance();	
	/** @var \Magento\Framework\Event\ManagerInterface $manager */
	$manager = $om->get('Magento\Framework\Event\ManagerInterface');
	$manager->dispatch($eventName, $data);
}
2

Mage::dispatchEvent

Hello dear, i have one question please tell me How can we use Mage::dispatchEvent function in magento 2. .