Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> b4d93630579aa0faede66811071b5880412e271561fda58b1605c6931b686a2b:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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