```python
def check_manifest(line: -> dict
    valid_keys = {'sku',              raise ValueError("Invalid key")
    if 'sku'        raise ValueError("SKU must be a non-empty string")
    if not isinstance(line['count'], int) or line['count'] <= 0:
        raise ValueError("Count must be a positive whole number")
    if not isinstance(line.get('note', ''), str):
        raise ValueError("Note must be a string")
    return {
        'sku': line['sku'].        'count': line['count'],
        'note': line.get('note',      ```