Python Command Line Argument Parser

PythonCommandLineArgumentParser.py

#!/usr/bin/env python3
"""
Implement command argument parser
"""
__author__ = "Aarsh Talati"
__version__ = "1.0.0"
__license__ = "GNU General Public License v3.0"

import sys

def main():
	"""Print greeting message
	"""
	print ("hello world")


if __name__ == "__main__":
	valid_options = ['--option1', '--option2']
	parameters = sys.argv[1:] + [None]
	options = {}
	key = None
	try:
		opts = [o for o in sys.argv[1:] if o.startswith("--")]
		if not all(o in valid_options for o in opts):
			raise ValueError
		for p in parameters:
			if p == None or p.startswith("--"):
				if key is not None:
					options[key[2:]] = values
				key = p
				values = []
			else:
				values.append(p)
		print(options)
		main()
	except NameError:
		print("Invalid syntax. Example: \"-- opt --opt arg arg --opt arg\"")
	except ValueError:
		print("Invalid option switch. Valid options: ", valid_options)