Flip the Score Map

In the old data format, the grouping is reversed: points come first, with a list of letters that share that value. The function transform receives legacy_data and converts it into a new dictionary where each key is a lowercase letter and each value is its score. The score keys arrive as strings, so convert them to integers before storing them.

Примеры

Ввод

{"1": ["A", "E", "I", "O", "U"]}

Вывод

{"a": 1, "e": 1, "i": 1, "o": 1, "u": 1}

Ввод

{"1": ["A"], "2": ["D"]}

Вывод

{"a": 1, "d": 2}

Ввод

{"4": ["F", "H"], "8": ["X"]}

Вывод

{"f": 4, "h": 4, "x": 8}

Нужно реализовать

def transform(legacy_data: dict) -> dict: