class Holidays::DateCalculator::WeekendModifier

def to_monday_if_weekend(date)

Used as a callback function.
Does not modify date if it is not a weekend.
Move date to Monday if it occurs on a Saturday on Sunday. 
def to_monday_if_weekend(date)
  return date unless date.wday == 6 || date.wday == 0
  to_next_weekday(date)
end