Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 6afa3e1b123c330dba6eb6a121a6b17f2b6d8a18dc8eeeebd70ab82f72d4b6b9:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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