code: def secret_from_transfer_task(
          transfer_task: Optional[TransferTask],
          secrethash: SecretHash,
  ) -> Optional[Secret]:
      
      assert isinstance(transfer_task, InitiatorTask)
  
      transfer_state = transfer_task.manager_state.initiator_transfers[secrethash]
  
      if transfer_state is None:
          return None
  
      return transfer_state.transfer_description.secret
docs: Return the secret for the transfer, None on EMPTY_SECRET.