Help me in solving ADVPPY143 problem

My issue

Result always showing error in hidden cases what is the solution for that

My code

def user_function():
    # Open files in respective modes
    input_filename = "/mnt/codechef/input.txt"
    output_filename = "/mnt/codechef/output.txt"
    try:
        with open(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())
        # Display the contents of output.txt
        with open(output_filename,"r") as output_file:
               for line in output_file:
                   print(line.strip())
    except IOError as e:
        print("An error occurred:", e)

Learning course: Python Programming
Problem Link: Read, do operations and output to another file in Python Programming