'Required:
nothing
Returns:
a new system string
Logic:
iterate through the system string and replace short options with long options'

def __sub_short_with_long(self):

    new_string = []
    sub_list = self.__short_long_dict.keys()
    for item in self.__system_string:
        if (item in sub_list):
            item = self.__short_long_dict[item]
        new_string.append(item)
    return new_string
