[Tutor] Better way to substitute text?

[William Allison]

Hi,
Just learning Python, on chapter 6 of Learning Python 2nd Ed.  So, on to 
the question.  Is there a better way to
implement the code below?  It scans a saved html file and highlights 
certain keywords is a bold, red font.  It works,
but I suppose I'm wondering if it's the "Pythonic" way.
Thanks,
Will

#!/usr/bin/env python

in_put = open('test.html', 'r')
out_put = open('test_highlight.html', 'a')

for line in in_put:
        line = line.replace("TWY", "<b><font 
color='#FF0000'>TWY</font></b>")
        line = line.replace("RWY", "<b><font 
color='#FF0000'>RWY</font></b>")
        line = line.replace("WIP", "<b><font 
color='#FF0000'>WIP</font></b>")
        out_put.write(line)

in_put.close()
out_put.close()