Google code jam input/output file handling in python

main.py

#!/usr/bin/python3
# Google code jam input/output file handling, implement process_input for the
# problem at hand
import argparse


def process_input(input):
    output = 0

    return output


if __name__ == "__main__":
    parser = argparse.ArgumentParser(description='Input File.')
    parser.add_argument('f', metavar='file', help='Input file')
    args = parser.parse_args()
    file_name = args.f

    output_lines = []
    with open(file_name) as f:
        first_input_line = True
        for input_line in f:
            if first_input_line:  # skip number of test cases
                first_input_line = False
                continue

            input = input_line.strip()
            output = process_input(input)
            print("{} -> {}".format(input, output))
            output_lines.append(output)

    # write output file:
    f = open('output', 'w')
    i = 1
    for l in output_lines:
        f.write("Case #{}: {}\n".format(i, l))
        i += 1