Question

Main objective:
function to read top score from text file.
Parameters to be passed onto function:
A text document!

def highscore():
    try:
        text_file = open ("topscore.txt", "r")
        topscore = int(text_file.read())
        print topscore
        text_file.close()
        return topscore
    except:
        print "Error - no file"
        topscore = 0
        return topscore

How to add a text file as a parameter?

Answer 1

def highscore(filename):
    try:
        text_file = open (filename, "r")

Oh, and you should stop putting more code than necessary into your try block. A clean solution would look like this:

def highscore(filename):
    if not os.path.isfile(filename):
        return 0
    with open(filename, 'r') as f:
        return int(f.read())

Or, if you prefer to return 0 in any case where reading the file fails:

def highscore(filename):
    try:
        with open(filename, 'r') as f:
            return int(f.read())
    except:
        return 0