Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 9bd02fdf37f56d37e0ccc9eb24fd7324a6d7e5a51cd2ee8763dd70a9ea5a3831:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

error: pre-condition failed: listing has already been purchased
   --> 4eb8a10cb9f87357.NFTStorefront:243:16