Transaction

[Error Code: 1101] cadence runtime error Execution failed:
error: unexpectedly found nil while forcing an Optional value
  --> 79a302df70045ca417f6be7d7853b0acfec8f481c7797bd314677274b3b068da:60:112
   |
60 |             let payment <- self.FlowTokenVault.withdraw(amount: prices[self.FlowTokenVault.getType().identifier]!.price)
   |                                                                                                                 ^