Sensor Mode

```
from hub import port

S1d = port.F.device
S2d = port.D.device
S1d.mode(4) #RREFL
S2d.mode(4) #RREFL

while True:
    print(str(S1d.get()[0]) + " , " +str(S2d.get()[0]))
```

This part doesn't work here. Do I have to install anything before?