Sample code to read in test cases

sample.py

# On CodeEval, test cases are read in from a file which is the first argument to your program
# Open the file and read in line by line. Each line represents a different test case
# (unless given different instructions in the challenge description)

import sys

test_cases = open(sys.argv[1], 'r')

for test in test_cases:
    # ignore test if it is an empty line
    # 'test' represents the test case, do something with it
    # ...
    # ...

test_cases.close()

I must be getting severely confused about how to run a program with input containing multiple lines. Can someone walk me through how to submit an answer for the challenge linked below? Basically sum of the lines. The actual function that would add up all of the numbers is easy enough, but I do not understand how to make my input be the different numbers from a file with multiple lines.

Working in Javascript.

https://www.codeeval.com/open_challenges/24/

What do i write as input and output filenames?

Here's some starter code for Fortran. #MakeFortranGreatAgain
program main
implicit none
character(32) :: tests
character(10) :: test
integer :: stat
!Get file name
call get_command_argument(1, arg)
!Open file
open (11,file=trim(arg),action='read')
do
!read in test
read (11,'(a)',iostat=stat) test
if (stat /= 0) exit
if (str /= '') then
.........
! Code goes here
.........
end if
end do
close (11)
end program main

Please show me an example for python3, if you need to pass a parameter to the function, how do I issue the code?