Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 4704dd3223f0c61d04d5685f1bbfd1ca86b7dd56b3d549b16ad95bd3e8163245:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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