如何使用python中的add函数？

import numpy as np

arr1 = np.array([[4, 7], [2, 6]],

                 dtype = np.float64)

arr2 = np.array([[3, 6], [2, 8]],

                 dtype = np.float64)

# Addition of two Arrays

Sum = np.add(arr1, arr2)

print("Addition of Two Arrays: ")

print(Sum)

fruits = {"a", "b", "c"}

fruits.add("d")

print(fruits)

{'a', 'b', 'c', 'd'}