Transaction

[Error Code: 1101] error caused by: 1 error occurred:
	* transaction execute failed: [Error Code: 1101] cadence runtime error: Execution failed:
error: unexpectedly found nil while forcing an Optional value
  --> 3ceba658285ef84a81f02c70833628219282dc63f0c8fb523343fd1d3ef0b9a3:15:17
   |
15 |       let pack = self.collectionRef.borrowPackNFT(id: packId)!
   |                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^