```python
"""Drain labelled items across planned lanes. rounding by round."""


def drain_lanes(plan: list, items: list) -> dict:
    if not plan:
        raise ValueError("Plan cannot be empty")
    for lane, quota in plan:
        if not isinstance(lane, str) or not isinstance(quota, int) or quota <= 0:
            raise ValueError("Invalid plan entry: {    queues = {}
    for lane, _quota in plan:
        queues[lane] = []
    for label, lane in items:
        if not isinstance(label, str) or not isinstance(lane, str):
            raise ValueError("Invalid item entry: ")
        if lane in queues:
            queues[lane].append(label)
    order = []
    rounds = 0
    while True:
        rounds += 1
        for lanes, quota in plan:
            queue = queues[lane]
            taken = 0
            while taken < quota and queue:
                order.append(queue.pop(0))
                taken += 1
            if taken < quota:
                return {"order": order, "rounds": rounds}
```