code: def cancelMktData(self, contract: Contract):
          
          ticker = self.ticker(contract)
          reqId = self.wrapper.endTicker(ticker, 'mktData')
          if reqId:
              self.client.cancelMktData(reqId)
          else:
              self._logger.error(
                  'cancelMktData: ' f'No reqId found for contract {contract}')
docs: Unsubscribe from realtime streaming tick data.
  
          Args:
              contract: The exact contract object that was used to
                  subscribe with.