Help me in solving ADVPPY145 problem

My issue

Coding problem 1

My code

def user_function():
    # Open files in respective modes
    input_filename = "/mnt/codechef/input.txt"
    output_filename = "/mnt/codechef/input.txt"
    try:
        with read(input_filename, 'r') as input_file, open(output_filename, 'w') as output_file:
            # Read and write the numbers from the file
            for line in input_file:
                number = int(line.strip())
                output_file.write(str(2 * number) + '\n')
            # Display the contents of output.txt
        with open(output_filename, 'r') as output_reader:
            for line in output_reader:
                print(line.strip())
    except IOError as e:
        print(e)  

Learning course: Python Programming
Problem Link: Coding problem 1 in Python Programming