Python 在下面的KNN算法中，有没有办法解决这个映射错误

我从youtube上引用了KNN算法在ML中的一个简单实现，但不知何故出现了以下错误

import pandas as pd

from sklearn.preprocessing import LabelEncoder


data = pd.read_csv('car.data')
print(data.head())

x = data[[
    'buying',
    'maint',
    'safety'
]].values

y = [['class']]

# print(x,y)
#
# copmversionn into numbers

le=LabelEncoder()

for i in range (len(x[0])):
    x[:,i] = le.fit_transform(x[:,i])

print(x)

# for y using mapping

lm = {
    'unacc':0,
    'acc':1,
    'good':2,
    'vgood':3
}

y['class'] = y['class'].map(lm)
print(y)