获取没有父键的嵌套字典的子键值

做一个递归函数是一个很好的猜测:

data = {'keyA':
  {'a': 'blue', 'b': {'b1': 'sky', 'b2': 'baby', 'b3': 'navy'},

'keyB':
  {'x': 'horse', 'y': {'y1': 'stallion', 'y2': 'thoroughbred'}, 'z': {'z1': 'white', 'z2': 'black'}},

'keyC': 'father'
 }}



def find_value(data, key):
    if not isinstance(data, dict):
        return None

    try:
        return data[key]
    except KeyError:
        for sub_data in data.values():
            sub_value = find_value(sub_data, key)
            if sub_value is not None:
                return sub_value

    return None

print(find_value(data, 'z1'))
# 'white'

print(find_value(data, 'z4'))
# None