How to use the workalendar.core.Calendar function in workalendar

return days

    def get_variable_days(self, year):
        days = super(CesarChavezDayMixin, self).get_variable_days(year)
        days.extend(self.get_chavez_day(year))
        return days


class DayAfterChristmasNoFloatMixin(Calendar):
    """26th of December - but doesn't ever float"""
    def get_day_after_christmas(self, year):
        days = (date(year, 12, 26), "Day After Christmas")
        return days


class PatriotsDayMixin(Calendar):
    """3rd Monday of April"""
    def get_patriots_day(self, year):
        days = (self.get_nth_weekday_in_month(year, 4, MON, 3),
                "Patriots Day")
        return days


class Alabama(UnitedStates, WesternCalendar, FloatToNearestWeekdayMixin):
    "Alabama"
    include_confederation_day = True

    def get_variable_days(self, year):
        days = super(Alabama, self).get_variable_days(year)
        days = self.float(days)
        days.extend([
            (Alabama.get_nth_weekday_in_month(year, 6, MON, 1),

WEEKEND_DAYS = (SAT, SUN)


class IslamicCalendar(IslamicMixin, Calendar):
    """
    Islamic calendar
    """


class IslamoWesternCalendar(IslamicMixin, WesternMixin, Calendar):
    """
    Mix of Islamic and Western calendars.

    When countries have both Islamic and Western-Christian holidays.
    """
    FIXED_HOLIDAYS = Calendar.FIXED_HOLIDAYS

class CesarChavezDayMixin(Calendar):
    """31st of March, float to 1st April if Monday"""
    def get_chavez_day(self, year):
        days = [(date(year, 3, 31), "Cesar Chavez Day")]
        if date(year, 3, 31).weekday() == SUN:
            days.append((date(year, 4, 1), "Cesar Chavez Day (Observed)"))
        return days

    def get_variable_days(self, year):
        days = super(CesarChavezDayMixin, self).get_variable_days(year)
        days.extend(self.get_chavez_day(year))
        return days


class DayAfterChristmasNoFloatMixin(Calendar):
    """26th of December - but doesn't ever float"""
    def get_day_after_christmas(self, year):
        days = (date(year, 12, 26), "Day After Christmas")
        return days


class PatriotsDayMixin(Calendar):
    """3rd Monday of April"""
    def get_patriots_day(self, year):
        days = (self.get_nth_weekday_in_month(year, 4, MON, 3),
                "Patriots Day")
        return days


class Alabama(UnitedStates, WesternCalendar, FloatToNearestWeekdayMixin):
    "Alabama"

(date(year, 5, 1), self.labour_day_label)
            )
        return days

    def get_variable_days(self, year):
        days = super().get_variable_days(year)
        new_year = date(year, 1, 1)
        if self.include_new_years_day and self.shift_new_years_day:
            if new_year.weekday() in self.get_weekend_days():
                days.append((
                    self.find_following_working_day(new_year),
                    "New Year shift"))
        return days


class WesternCalendar(WesternMixin, Calendar):
    """
    A Christian calendar using Western definition for Easter.
    """


class OrthodoxCalendar(OrthodoxMixin, Calendar):
    """
    A Christian calendar using Orthodox definition for Easter.
    """


class ChineseNewYearCalendar(ChineseNewYearMixin, Calendar):
    """
    Chinese Calendar, using Chinese New Year computation.
    """
    # There are regional exceptions to those week-end days, to define locally.

from ..core import Calendar
from ..core import FRI, SAT, IslamicMixin
from ..registry_tools import iso_register


@iso_register('QA')
class Qatar(IslamicMixin, Calendar):
    "Qatar"
    WEEKEND_DAYS = (FRI, SAT)

    FIXED_HOLIDAYS = (
        (12, 18, "National Day"),
    )
    include_start_ramadan = True
    include_eid_al_fitr = True
    length_eid_al_fitr = 4
    include_eid_al_adha = True
    length_eid_al_adha = 4

elif christmas_day == FRI:
            day = date(year, 12, 24)  # THU
        elif christmas_day == SAT:
            day = date(year, 12, 23)  # THU
        else:  # christmas_day == SUN:
            day = date(year, 12, 23)  # FRI
        return (day, self.label_washington_bday_observed)

    def get_variable_days(self, year):
        days = super(WashingtonsBirthdayInDecemberMixin, self) \
            .get_variable_days(year)
        days.append(self.get_washington_birthday(year))
        return days


class CesarChavezDayMixin(Calendar):
    """31st of March, float to 1st April if Monday"""
    def get_chavez_day(self, year):
        days = [(date(year, 3, 31), "Cesar Chavez Day")]
        if date(year, 3, 31).weekday() == SUN:
            days.append((date(year, 4, 1), "Cesar Chavez Day (Observed)"))
        return days

    def get_variable_days(self, year):
        days = super(CesarChavezDayMixin, self).get_variable_days(year)
        days.extend(self.get_chavez_day(year))
        return days


class DayAfterChristmasNoFloatMixin(Calendar):
    """26th of December - but doesn't ever float"""
    def get_day_after_christmas(self, year):

if (date(year, 12, 25) in holiday_lookup and
                date(year, 12, 24) in holiday_lookup and
                date(year, 12, 25).weekday() == SAT):
            new_holidays.append((date(year, 12, 23),
                                 "Christmas Eve (Observed)"))
        if (date(year, 12, 25) in holiday_lookup and
                date(year, 12, 24) in holiday_lookup and
                date(year, 12, 25).weekday() == MON):
            new_holidays.append((date(year, 12, 26),
                                 "Christmas Eve (Observed)"))
            new_holidays.append((date(year, 12, 27),
                                 "Christmas Day (Observed)"))
        return holidays + new_holidays


class WashingtonsBirthdayInDecemberMixin(Calendar):
    """Floating observance, to give long weekend at christmas.

    It's only observed in Georgia and Indiana.
    """
    label_washington_bday_observed = "Washington's Birthday (Observed)"

    def get_washington_birthday(self, year):
        christmas_day = date(year, 12, 25).weekday()
        if christmas_day == MON:
            day = date(year, 12, 26)  # TUE
        elif christmas_day == TUE:
            day = date(year, 12, 24)  # MON
        elif christmas_day == WED:
            day = date(year, 12, 24)  # TUE
        elif christmas_day == THU:
            day = date(year, 12, 26)  # FRI

return days


class WesternCalendar(WesternMixin, Calendar):
    """
    A Christian calendar using Western definition for Easter.
    """


class OrthodoxCalendar(OrthodoxMixin, Calendar):
    """
    A Christian calendar using Orthodox definition for Easter.
    """


class ChineseNewYearCalendar(ChineseNewYearMixin, Calendar):
    """
    Chinese Calendar, using Chinese New Year computation.
    """
    # There are regional exceptions to those week-end days, to define locally.
    WEEKEND_DAYS = (SAT, SUN)


class IslamicCalendar(IslamicMixin, Calendar):
    """
    Islamic calendar
    """


class IslamoWesternCalendar(IslamicMixin, WesternMixin, Calendar):
    """
    Mix of Islamic and Western calendars.

# Inauguration day
        if UnitedStates.is_presidential_year(year - 1):
            inauguration_day = date(year, 1, 20)
            if inauguration_day.weekday() == SUN:
                inauguration_day = date(year, 1, 21)
            days.append((inauguration_day, "Inauguration Day"))

        if self.include_thanksgiving_friday:
            days.append(
                self.get_thanksgiving_friday(year)
            )
        return days


class FloatToNearestWeekdayMixin(Calendar):
    "Float Saturady to Friday, Sunday to Monday"
    def float(self, holidays, year=0):
        new_holidays = []
        holiday_lookup = [x[0] for x in holidays]
        for holiday in holidays:
            if holiday[0].weekday() == SAT:
                new_holidays.append((holiday[0] - timedelta(days=1),
                                     holiday[1] + " (Observed)"))
            elif holiday[0].weekday() == SUN:
                new_holidays.append((holiday[0] + timedelta(days=1),
                                     holiday[1] + " (Observed)"))

        if year > 0 and date(year + 1, 1, 1).weekday() == SAT:
            new_holidays.append((date(year, 12, 31,),
                                 "New Years Day (Observed)"))

new_year = date(year, 1, 1)
        if self.include_new_years_day and self.shift_new_years_day:
            if new_year.weekday() in self.get_weekend_days():
                days.append((
                    self.find_following_working_day(new_year),
                    "New Year shift"))
        return days


class WesternCalendar(WesternMixin, Calendar):
    """
    A Christian calendar using Western definition for Easter.
    """


class OrthodoxCalendar(OrthodoxMixin, Calendar):
    """
    A Christian calendar using Orthodox definition for Easter.
    """


class ChineseNewYearCalendar(ChineseNewYearMixin, Calendar):
    """
    Chinese Calendar, using Chinese New Year computation.
    """
    # There are regional exceptions to those week-end days, to define locally.
    WEEKEND_DAYS = (SAT, SUN)


class IslamicCalendar(IslamicMixin, Calendar):
    """
    Islamic calendar