Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> a7efe789de2c4a904001d94d350d2987f11bdd76a07016755b4f57140c798e97:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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