Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> a6bbf695a59f8eb4e893c7bb78ab807c7d1d38adec4ba397b2b8fa5e7e474f5f:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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