AttributeError: 'Korea' object has no attribute 'korean_cal'

[seriousran]

To solve this issue #1437 in prophet by @chongdae and this PR #1438 in prophet

cc @chongdae @1kko

code1:

import holidays
import numpy as np

holidays.__version__

output:

'0.10.2'

code2:

holidays.Korea(years=np.arange(1995, 2045))

output:

---------------------------------------------------------------------------
AttributeError                            Traceback (most recent call last)
<ipython-input-16-a964978a10b6> in <module>
----> 1 holidays.Korea(years=np.arange(1995, 2045))

~/anaconda3/envs/tf36/lib/python3.7/site-packages/holidays/countries/korea.py in __init__(self, **kwargs)
     33     def __init__(self, **kwargs):
     34         self.country = "KR"
---> 35         HolidayBase.__init__(self, **kwargs)
     36         self.korean_cal = KoreanLunarCalendar()
     37 

~/anaconda3/envs/tf36/lib/python3.7/site-packages/holidays/holiday_base.py in __init__(self, years, expand, observed, prov, state)
     32         self.state = state
     33         for year in list(self.years):
---> 34             self._populate(year)
     35 
     36     def __setattr__(self, key, value):

~/anaconda3/envs/tf36/lib/python3.7/site-packages/holidays/countries/korea.py in _populate(self, year)
     59         second_day_lunar = "The second day of " + name
     60 
---> 61         dt = self.get_solar_date(year, 1, 1)
     62         new_year_date = date(dt.year, dt.month, dt.day)
     63         if self.observed and year >= 2015:

~/anaconda3/envs/tf36/lib/python3.7/site-packages/holidays/countries/korea.py in get_solar_date(self, year, month, day)
    187     # convert lunar calendar date to solar
    188     def get_solar_date(self, year, month, day):
--> 189         self.korean_cal.setLunarDate(year, month, day, False)
    190         return date(self.korean_cal.solarYear, self.korean_cal.solarMonth,
    191                     self.korean_cal.solarDay)

AttributeError: 'Korea' object has no attribute 'korean_cal'

[dr-prodigy]

Merged, thank you very much! 👍