```python
def swipe_dedupe(swipes: list) -> list:
    """Drop any swipe that simply repeats the one immediately before it."""
    if not swipes:
        return []

    deduped_swipes = [swipes[0]]
    for swipe in swipes[1:]:
        if swipe != deduped_swipes[-1]:
            deduped_swipes.append(swipe)

    return deduped_swipes
```