Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 5f9bf8e5be1190cb086ce60c8edb3d5efa3bbc7970fdb196b0f0d7f99f6d7bab:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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