Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 56d9927786fb2345685ec1f7ab71708aff9ac108a3c4500906e84fe8cdc27273:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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