在PHP中反序列化数据

Item_id= 123200194926 and transaction_id=1970816179002

How can I get the item_id and transaction_id from the below

a: 1: {
  s: 16: "m2epro_extension";
  a: 1: {
    s: 5: "items";
    a: 1: {
      i: 0;
      a: 2: {
        s: 7: "item_id";
        s: 12: "123200194926";
        s: 14: "transaction_id";
        s: 13: "1970816179002";
      }
    }
  }
}

I got the solution:

print_r(unserialize($_item->getAdditionalData()));

Result:

Array
(
    [m2epro_extension] => Array
        (
            [items] => Array
                (
                    [0] => Array
                        (
                            [item_id] => 123200194926
                            [transaction_id] => 1970816179002
                        )

                )

        )

)