Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 50b246b6a6e389ce7f7232d287cc3edd44f0f59b3dfbab51a7a5922e95b0cf1e:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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