Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 77ec4aa5a100696cccf78bf758b82920e1ea167d05c8b62e95f3ca88c4368846:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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