Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 70088660d8027c883b63e0e4e45a7da085476f550e817351c7daf573677d2018:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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