Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> bd6ae4713a5ba8c41a5ad5ef22e4ef705ce998dfcba2cfcae5aa16ab201a0f12:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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