Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 04fcf769e0a4a7dbbbaf79b1a9415b701f958b0f4f4b2c6b4aa7464f5f4e1b97:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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