def _GetDaysPerMonth(self, year, month):
if month not in range(<NUM_LIT:1>, <NUM_LIT>):<EOL><INDENT>raise ValueError('<STR_LIT>')<EOL><DEDENT>days_per_month = self._DAYS_PER_MONTH[month - <NUM_LIT:1>]<EOL>if month == <NUM_LIT:2> and self._IsLeapYear(year):<EOL><INDENT>days_per_month += <NUM_LIT:1><EOL><DEDENT>return days_per_month<EOL>
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.