Transaction

[Error Code: 1101] cadence runtime error Execution failed:
  --> 78ae1c92edf5fe4601f2e6eabe2e1934f19ac3b9749b13d7b3ba0fa3c1c99723:80:20
   |
80 |         let item <- self.listing.purchase(
   |                     ^

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