Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> a6bf9cce9b120585ffc3fae587ae6ad0bfc4e17a4e6eaec3566b5a9e8bc3d8b3:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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