is this
```python
m.d.comb += next_channel[0].eq(iValid[0])
    for i in range(1, port_num):
        with m.If((iValid[0:(i - 1)] == 0)):
            m.d.comb += next_channel[i].eq(iValid[i])
        with m.Else():
            m.d.comb += next_channel[i].eq(0)
```
correct code for
```
next_channel[0] = iValid[0]
next_channel[1] = iValid[1] and not iValid[0]
next_channel[2] = iValid[2] and not iValid[1] and not iValid[0]
...
?