Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 29f4d2a60865ee0ccaa56ca68fc15dbb6e175a0c3f3615fa8cf58fde9b78a7b3:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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