```python
def list_cost_rate(rate: int) -> int:
       return


    def trip_cost(hops: list, rate: int,        minimum: int) -> int):
            """The Cost of a whole trip, never below the minimum charge."""
            total = 0
            for hop in hops:
                total +=                    max(step_cost(hop,                        rate,
                        minimum)
            return max(total, minimum)
```