add contract

common/components/Helper.php

@@ -6,10 +6,20 @@ use \Yii;
 
 class Helper {
 	
-	public static function getDateTimeString(){
+	public static function getDateTimeString( ){
+		
 		return date("Y-m-d H:i:s");
 	}
 	
+	public static function  getArrayValue($arr,$key,$def){
+		$result = $def;
+		if ( array_key_exists($key, $arr)){
+			$result = $arr[$key];
+		}
+		return $result;
+	}
+	
+	
 	public static function hufRound($m) {
 		$result = round ( $m / 5, 0 ) * 5;
 		return $result;