Return a list of user input
        :param input_string:
        :return:

def get_list(self, input_string):
        """
        Return a list of user input
        :param input_string:
        :return:
        """

        if input_string in ('--ensemble_list', '--fpf'):

            # was the flag set?
            try:
                index_low = self.args.index(input_string) + 1
            except ValueError:
                if input_string in self.required:
                    print("\n {flag} is required".format(flag=input_string))
                    print_short_help()
                    sys.exit(1)
                else:
                    return None

            # the flag was set, so check if a value was set, otherwise exit
            try:
                if self.args[index_low] in self.flags:
                    print("\n {flag} was set but a value was not specified".format(flag=input_string))
                    print_short_help()
                    sys.exit(1)
            except IndexError:
                print("\n {flag} was set but a value was not specified".format(input_string))
                print_short_help()
                sys.exit(1)

            # at least one value was set
            index_high = index_low
            try:
                # if the flag wasn't the last argument specified
                while self.args[index_high] not in self.flags:
                    index_high += 1
            except IndexError:
                # if it was, then handle it accordingly
                index_high = self.args.index(self.args[-1])
                return self.args[index_low:index_high + 1]
            # return a list of input files
            if index_low == index_high:
                inputList = []
                inputList.append(self.args[index_low])
                return inputList
            else:
                return self.args[index_low:index_high]