I'm try to work out how to use optparse, but I've come to a problem.

My script (represented by this simplified example) takes a file, and does different things to it depending on options that are parsed to it. If no options are parsed nothing is done.

It makes sense to me that because of this, an error should be given if no options are given by the user. I can't work out how to do this.

Am I using options in the wrong way? If so, how should I be doing it instead?

#!/usr/bin/python

from optparse import OptionParser

dict = {'name': foo, 'age': bar}

parser = OptionParser()

parser.add_option("-n", "--name", dest="name")
parser.add_option("-a", "--age", dest="age")

(options, args) = parser.parse_args()

if options.name:
    dict['name'] = options.name

if options.age:
    dict['age'] = options.age

print dict

#END