BSON-progra inter

{
    _id:ObjectId('bca678b67a68b76ca'),
    username:'Pepito',
    password:'C0nT_4SeN-@!;',
    files:
        [

            {
                _id:ObjectId('c7a8b9a7c89b7a98bac78'),
                name:'Hoja 1',
                cells:
                    [
                        {
                            _id:ObjectId('a8cb9ac8b90a8c09a8'),
                            row:1,
                            column:'a',
                            value:'25'
                        },
                        ...
                    ]
            },
            ...
        ]
}