All inline comments should come with a space after the #. All dictionary literals should have no spaces immediately within { and }. All multi-line dictionaries should be aligned one character after the opening parenthesis. There exists a line with "for key, value in dict.items.():", which is invalid. Use of one-liner "for" statements is discouraged. "if not a in b" is a more easily translatable statement than "if a not in b".