code: def scan(cls, formats=ALL_CODE_TYPES, camera=-1):
          
          app = AndroidApplication.instance()
          r = app.create_future()
  
              #: Initiate a scan
          pkg = BarcodePackage.instance()
          pkg.setBarcodeResultListener(pkg.getId())
          pkg.onBarcodeResult.connect(r.set_result)
  
          intent = cls(app)
          if formats:
              intent.setDesiredBarcodeFormats(formats)
          if camera != -1:
              intent.setCameraId(camera)
          intent.initiateScan()
  
          return r
docs: Shortcut only one at a time will work...