import string

import random

import re

def gen_key(no_of_chars):

    allowed_chars = string.digits+string.uppercase

    return ''.join([random.choice(allowed_chars) for i in range(no_of_chars)])

def correct_quiz(quiz):

    """ read each submitted answer and update the is_correct variable.

    """

    for answer in quiz.que_answered.all():

        expected_ans = answer.question.expected_ans

        ans_regex_patterns = []

        for ans_pattern in expected_ans.split("\n"):

            ans_regex_patterns.append( r"\s*".join(ans_pattern.split()) if not re.match(r"""^[",']""", ans_pattern) else ans_pattern )

        for pattern in ans_regex_patterns:

            if re.findall(pattern, answer.submitted_ans):

                answer.is_correct = True

                answer.save()

                break