Class IllegalMonthError

Lib/calendar.py:32–36

# This is trick for backward compatibility. Since 3.13, we will raise IllegalMonthError instead of
# IndexError for bad month number(out of 1-12). But we can't remove IndexError for backward compatibility.
class IllegalMonthError(ValueError, IndexError):
    def __init__(self, month):
        self.month = month
    def __str__(self):
        return "bad month number %r; must be 1-12" % self.month


class IllegalWeekdayError(ValueError):