string_template_missing.py

#!/usr/bin/env python

import string

values = {'var': 'foo'}

t = string.Template("$var is here but \
                    $missing is not provided")

try:
    print 'substitute() t.substitute(values):',
except KeyError, err:
    print 'ERROR:', str(err)

print 'safe_substitute():',
t.safe_substitute(values)