code: def _GetDaysPerMonth(self, year, month):
      
      if month not in range(1, 13):
        raise ValueError('Month value out of bounds.')
  
      days_per_month = self._DAYS_PER_MONTH[month - 1]
      if month == 2 and self._IsLeapYear(year):
        days_per_month += 1
  
      return days_per_month
docs: Retrieves the number of days in a month of a specific year.
  
      Args:
        year (int): year e.g. 1970.
        month (int): month, where 1 represents January.
  
      Returns:
        int: number of days in the month.
  
      Raises:
        ValueError: if the month value is out of bounds.