Kata

Sometimes it's useful to know on which day of the week Christmas, the holly holiday, will occur.
Write a function which takes the date of Christmas, and outputs the day of the week it falls on. Just don't limit yourself to this year.

Example:

findOutChristmasWeekday('2013 12 25') // returns 'Wednesday'

findOutChristmasWeekday '2013 12 25' # returns 'Wednesday'

find_out_christmas_weekday('2013 12 25') # returns 'Wednesday'

Only valid Christmas dates will be passed to the function.

Date parameter could be a string or a Date object. If it's a string here are possible date parameter formats:

'2013 12 25'
'12 25 2013'
'25 December 2013'

Note: calendar used in the kata is Gregorian.