How can I pass a filename as a parameter into my module

import re

regex = re.compile(
    r"""ULLAT: (?P<ullat>-?[d.]+).*?
    ULLON: (?P<ullon>-?[d.]+).*?
    LRLAT: (?P<lrlat>-?[d.]+)""", re.DOTALL|re.VERBOSE)

QUADNAME: rockport_colony_SD
RESOLUTION: 10 ULLAT: 43.625 ULLON:
-97.87527466 LRLAT: 43.5 LRLON: -97.75027466 HDATUM: 27 ZMIN: 361.58401489 ZMAX: 413.38400269 ZMEAN: 396.1293335 ZSIGMA: 12.36359215 PMETHOD: 5 QUADDATE: 20001001

$ py-file file-to-be-processed