'Returns the month number for a month specified by name or abbreviation.
:param name: the month name or abbreviation.'

def month_number(self, name):

    if (self._month_name_to_ordinal is None):
        self._month_name_to_ordinal = self._name_to_ordinal(self.month_names)
        self._month_name_to_ordinal.update(self._name_to_ordinal(self.month_abbreviations))
    return self._month_name_to_ordinal.get(name)
