def parse_options():
    usage = """%prog [options] [INPUTFILE]
       (STDIN is assumed if no INPUTFILE is given)"""
    desc = "A Python implementation of John Gruber's Markdown. " \
           "http://www.freewisdom.org/projects/python-markdown/"
    ver = "%%prog %s" % markdown.version
    
    parser = optparse.OptionParser(usage=usage, description=desc, version=ver)
    parser.add_option("-f", "--file", dest="filename", default=sys.stdout,
                      help="Write output to OUTPUT_FILE. Defaults to STDOUT.",
                      metavar="OUTPUT_FILE")
    parser.add_option("-e", "--encoding", dest="encoding",
                      help="Encoding for input and output files.",)
    parser.add_option("-q", "--quiet", default = CRITICAL,
                      action="store_const", const=CRITICAL+10, dest="verbose",
                      help="Suppress all warnings.")
    parser.add_option("-v", "--verbose",
                      action="store_const", const=INFO, dest="verbose",
                      help="Print all warnings.")
    parser.add_option("-s", "--safe", dest="safe", default=False,
                      metavar="SAFE_MODE",
                      help="'replace', 'remove' or 'escape' HTML tags in input")
    parser.add_option("-o", "--output_format", dest="output_format", 
                      default='xhtml1', metavar="OUTPUT_FORMAT",
                      help="'xhtml1' (default), 'html4' or 'html5'.")
    parser.add_option("--noisy",
                      action="store_const", const=DEBUG, dest="verbose",
                      help="Print debug messages.")
    parser.add_option("-x", "--extension", action="append", dest="extensions",
                      help = "Load extension EXTENSION.", metavar="EXTENSION")
    parser.add_option("-n", "--no_lazy_ol", dest="lazy_ol", 
                      action='store_false', default=True,
                      help="Observe number of first item of ordered lists.")

    (options, args) = parser.parse_args()

    if len(args) == 0:
        input_file = None
    else:
        input_file = args[0]

    if not options.extensions:
        options.extensions = []

    return {'input': input_file,
            'output': options.filename,
            'safe_mode': options.safe,
            'extensions': options.extensions,
            'encoding': options.encoding,
            'output_format': options.output_format,
            'lazy_ol': options.lazy_ol}, options.verbose
Return a list of names of input nodes to a component.
dataset/ETHPy150Open darcyliu/storyboard/markdown/__main__.py/parse_options--crossover with--dataset/ETHPy150Open OpenMDAO/OpenMDAO-Framework/openmdao.main/src/openmdao/main/depgraph.py/DependencyGraph.list_inputs