Transaction

[Error Code: 1101] error caused by: 1 error occurred:
	* transaction invocation failed when executing transaction: [Error Code: 1101] cadence runtime error: Execution failed:
  --> 9c5ba0b0009a7928c6463ec954669d9a929bbf657c3334b0730a44aa800eb4f3:81:20
   |
81 |         let item <- self.listing.purchase(
   |                     ^

error: pre-condition failed: listing has already been purchased
   --> 4eb8a10cb9f87357.NFTStorefrontV2:306:16