Random Method of selecting 2 contestants from a list

contestpicker.py

import random

# Implementation of Resevoir Algorithm, see
# http://stackoverflow.com/a/3540315/1424361
def random_line(contestants):
    line = next(contestants)
    line2 = line
    # go through each line, check to see if we 
    # should select it, with decreasing probability 
    # over time
    for num, aline in enumerate(contestants):
        if not random.randrange(num + 2):
            line = aline
        if not random.randrange(num + 2):
            line2 = aline
    return line + line2


if __name__ == "__main__":
    contestants = open('contestlist.csv','r')
    print random_line(contestants)