'Escape backslashes found inside a string quote.
Backslashes followed by anything other than [\'"rnbt] will just be included
in the string.
Args:
string: The string that matched.
match: The match object (m.group(1) is the escaped code)'

def StringEscape(self, string, match, **_):

    if (match.group(1) in '\'"rnbt'):
        self.string += string.decode('string_escape')
    else:
        self.string += string
