Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 30e96eed8e432d121ae3b3624eed756d4edd0fe4d3ddfe0bab8030a0a2cf1ff6:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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