我应该如何用python创建隐式评分矩阵？

import numpy as np
import pandas as pd

data = pd.DataFrame({'user_id': [1, 1, 2, 2, 3],
                     'item_id': [100, 200, 100, 300, 200],
                     'rating': [1, 1, 1, 1, 1]})

implicit_matrix = pd.pivot_table(data, values='rating', index='user_id', columns='item_id', aggfunc=np.sum, fill_value=0)

implicit_matrix_normalized = implicit_matrix / implicit_matrix.max()