4维嵌套字典到pandas数据框架

import pandas as pd

data = {
    'A': {
        'a': {
            '1': {'x': 1, 'y': 2},
            '2': {'x': 3, 'y': 4}
        },
        'b': {
            '1': {'x': 5, 'y': 6},
            '2': {'x': 7, 'y': 8}
        }
    },
    'B': {
        'a': {
            '1': {'x': 9, 'y': 10},
            '2': {'x': 11, 'y': 12}
        },
        'b': {
            '1': {'x': 13, 'y': 14},
            '2': {'x': 15, 'y': 16}
        }
    }
}

df = pd.DataFrame.from_dict({(i, j, k, l): data[i][j][k][l] 
                             for i in data.keys() 
                             for j in data[i].keys() 
                             for k in data[i][j].keys() 
                             for l in data[i][j][k].keys()},
                            orient='index')

df = df.reset_index()