Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 6f2c64cf5c3f7a1acdef68ca3b0f7cee12ca9fbfce543d83ce2811ca854bea1d:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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