Lesson 6.1 grading syntax error

[paulkm]

The grading RegEx for exercise 6.1 results in a Python syntax error for escaping the parentheses as the python string formatter attempts to parse the escape sequence before passing it on to the regex parser. The fix is to specify the regex strings as 'raw' like so:

REGEX_CATEGORIES = {
    "A": r"A\) P",
    "B": r"B\) B",
    "C": r"C\) B",
    "D": r"D\) O"
}