how to append rows to a numpy matrix

import numpy as np    
arr = np.empty((0,3), int)
print("Empty array:")
print(arr)
arr = np.append(arr, np.array([[10,20,30]]), axis=0)
arr = np.append(arr, np.array([[40,50,60]]), axis=0)
print("After adding two new arrays:")
print(arr)

Here is what the above code is Doing:
1. Create an empty array with 0 rows and 3 columns.
2. Add a new row to the array with the values 10, 20, 30.
3. Add a new row to the array with the values 40, 50, 60.
4. Print the resulting array.