Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 4b1d1e8f39d9ee1b9f0496b7b240370215ad001a6b4bd73de1948881ac7a4ec3:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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