<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def reqScannerData( self, subscription: ScannerSubscription, scannerSubscriptionOptions: List[TagValue] = None, scannerSubscriptionFilterOptions: List[TagValue] = None) -> ScanDataList: """ Do a blocking market scan by starting a subscription and canceling it after the initial list of results are in. This method is blocking. https://interactivebrokers.github.io/tws-api/market_scanners.html Args: subscription: Basic filters. scannerSubscriptionOptions: Unknown. scannerSubscriptionFilterOptions: Advanced generic filters. """

        return self._run(
            self.reqScannerDataAsync(
                subscription, scannerSubscriptionOptions,
                scannerSubscriptionFilterOptions))