参数类型“Object”无法分配给参数类型“Map ？”

我遇到过这个错误：

The argument type 'Object' can't be assigned to the parameter type 'Map<String, dynamic>?

在这行代码中：

 listMakans = query.docs.map((m) => Makan.fromSnapshot(m.data()!)).toList();

这是（Makan.fromSnapshot）的代码：

Makan.fromSnapshot(Map<String, dynamic>? snapshot)
      : id = snapshot!['id'],
        owner = snapshot['owner'],
        category = snapshot['category'],
        hobby = snapshot['hobby'],
        business = snapshot['business'],
        title = snapshot['title'],
        details = snapshot['details'],
        latlng = snapshot['latlng'],
        from = snapshot['from'].toDate(),
        to = snapshot['to'].toDate(),
        created = snapshot['created'].toDate(),
        updated = snapshot['updated'].toDate();

我不明白这里的对象在哪里？

listMakans = query.docs.map((m) => Makan.fromSnapshot(m.data() as Map<String, dynamic>?)).toList();