Transaction

[Error Code: 1101] cadence runtime error Execution failed:
error: unexpectedly found nil while forcing an Optional value
  --> f307f2fc9b7015520a8de9b95886d2f6f9c47b80c2b414da177cf82b3c8cdf62:60:112
   |
60 |             let payment <- self.FlowTokenVault.withdraw(amount: prices[self.FlowTokenVault.getType().identifier]!.price)
   |                                                                                                                 ^