Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 5f277ee1f0f26bef6355199bd5d5c1afe4004b1fb5c58caa82d1ebf9ad03b4a2:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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