class DateRangeSequence:
def init(self, state_date, end_date):
self.start_date = start_date
self.end_date = end_date
self._range = self._create_range()
Correct:
class DateRangeSequence:
def init(self, start_date, end_date):
self.start_date = start_date
self.end_date = end_date
self._range = self._create_range()