diff --git a/system/libraries/Session/Session.php b/system/libraries/Session/Session.php
index 81d63c3..910b999 100644
--- a/system/libraries/Session/Session.php
+++ b/system/libraries/Session/Session.php
@@ -389,18 +389,18 @@
 	/**
 	 * Keeps existing flashdata available to next request.
 	 *
-	 * @param	mixed	Item key
+	 * @param	mixed	Item key(s)
 	 * @return	void
 	 */
 	public function keep_flashdata($data)
 	{
 		// Wrap item as array if singular
-		if (is_string($data))
+		if (!is_array($data))
 		{
 			$data = array($data);
 		}
 
-		foreach($data as $key)
+		foreach ($data as $key)
 		{
 			// 'old' flashdata gets removed. Here we mark all flashdata as 'new' to preserve it from _flashdata_sweep()
 			// Note the function will return NULL if the $key provided cannot be found
@@ -410,7 +410,6 @@
 			$new_flashdata_key = self::FLASHDATA_KEY.self::FLASHDATA_NEW.$key;
 			$this->set_userdata($new_flashdata_key, $value);
 		}
-
 	}
 
 	// ------------------------------------------------------------------------