A sample python script using argParse

sampleArgParse.py

#!/usr/bin/env python3
import asyncio
import aiohttp
from aiohttp import ClientSession

import argparse

import re

class StoreDictKeyPair(argparse.Action):
    def __init__(self, option_strings, dest, nargs=None, **kwargs):
         self.myDict = {}
         super(StoreDictKeyPair, self).__init__(option_strings, dest, nargs=nargs, **kwargs)
    def __call__(self, parser, namespace, values, option_string=None):
        k,v = values.split(":")
        self.myDict.update({k:v})
        setattr(namespace, self.dest, self.myDict)

parser = argparse.ArgumentParser(description="[state intent]\nExample command: %(prog)s https://url.here/endpoint",
    usage='use "%(prog)s --help" for more information',
    formatter_class=argparse.RawTextHelpFormatter)
parser.add_argument("-u", "--user", help= "credentials in the form user:password",type=str,metavar= "")
parser.add_argument("-H", "--header",help= "additional header for request", action=StoreDictKeyPair ,default = {},metavar= "",dest='header')
parser.add_argument("-d", "--data", help="data to send with request",type=str,metavar= '')
parser.add_argument("-X","--call-type",help="request type to use", type=str,default="GET",metavar= '',choices=["GET","POST","PUT","DELETE"])
parser.add_argument("url",help="url to use",type=str)
args = parser.parse_args()

def parseURLList(url):
    urlList = []
    subString = re.search(r"\[(.*?)\]|\{(.*?)\}", url)
    if subString == None:
        urlList.append(url)
        return urlList
    elif subString.group(0).startswith('['):
        parseStep = re.split(":",subString.group(0).strip('[]'))   
        nth = 1
        if len(parseStep) > 1:
            nth = int(parseStep[1])
        parseRange = re.split("-",parseStep[0])   
        start = int(parseRange[0])
        end = int(parseRange[1])
        for x in range(start,end,nth):
            modifiedUrl = re.sub(r"\[(.*?)\]",str(x),url,1)
            urlList += parseURLList(modifiedUrl) or []
    elif subString.group(0).startswith('{'):
        parseElems = re.split(",",subString.group(0).strip('{}'))   
        for x in parseElems:
            modifiedUrl = re.sub(r"\{(.*?)\}",x,url,1)
            urlList += parseURLList(modifiedUrl) or []
    return urlList

print(args)
print(parseURLList(args.url))