if (! function_exists('getCacheSettings')){	function getCacheSettings($key)	{	if ($cacheSettingValue = checkCachedValue($key)) {	return $cacheSettingValue;	}	$ci = & get_instance();	$result = $ci->db->get_where('settings', array('key' => $key));	if ($result->num_rows() > 0) {	$fetchData = $result->row();	cacheFetchedData($key, base64_decode($fetchData->value));	return base64_decode($fetchData->value);	}	return null;	}
}
if (! function_exists('checkCachedValue')){	function checkCachedValue($key)	{	$ci = & get_instance();	$ci->load->driver('cache', array('adapter' => 'file'));	$cacheKeyData = $ci->cache->get("icd10_".$key);	return !empty($cacheKeyData) ? $cacheKeyData : false;	}
}
if (! function_exists('cacheFetchedData')){	function cacheFetchedData($key, $fetchedData)	{	$ci = & get_instance();	$ci->load->driver('cache', array('adapter' => 'file'));	// Save into the cache for 12 Hours	$ci->cache->save('icd10_'.$key, $fetchedData, 60 * 60 * 12);	return $fetchedData;	}
}
getCacheSettings('KEY_NAME');
$this->cache->delete('cache_item_id');
This method will ‘clean’ the entire cache. If the deletion of the cache files
fails, the method will return FALSE.
$this->cache->clean();
refrence:
https://www.codeigniter.com/userguide3/libraries/caching.html#example-usage

class MY_Output extends CI_Output