Essentially, the two pipes, pipe_1 and pipe_2, are created by the multiprocessing.Pipe(True) statement:

pipe_1 = multiprocessing.Pipe(True)
pipe_2 = multiprocessing.Pipe(True)

The first pipe, pipe_1, simply created a list of integers from 0 to 9, while the second pipe, pipe_2, processed each element of the list created by pipe_1, calculating the squared value of each element:

process_pipe_2 = 
                   multiprocessing.Process
                   (target=multiply_items, args=(pipe_1, pipe_2,))

Therefore, both processes are closed:

pipe_1[0].close()
pipe_2[0].close()

And the final result is printed:

print (pipe_2[1].recv())

Execute the code by typing the following command:

> python communicating_with_pipe.py

The following result shows the square of the first 9 digits:

0
1
4
9
16
25
36
49
64
81