def valid_date(s):
try:
return datetime.strptime(s, "%Y-%m-%d")
except ValueError:
msg = "Not a valid date: '{0}'.".format(s)
raise argparse.ArgumentTypeError(msg)
parser.add_argument("-s",
"--startdate",
help="The Start Date - format YYYY-MM-DD",
required=True,
type=valid_date)