Initialize form map

def _init_map(self, record_types=None, **kwargs):
        """Initialize form map"""
        osid_objects.OsidObjectForm._init_map(self, record_types=record_types)
        self._my_map['numericScoreIncrement'] = self._numeric_score_increment_default
        self._my_map['lowestNumericScore'] = self._lowest_numeric_score_default
        self._my_map['basedOnGrades'] = self._based_on_grades_default
        self._my_map['highestNumericScore'] = self._highest_numeric_score_default
        self._my_map['assignedGradebookIds'] = [str(kwargs['gradebook_id'])]
        self._my_map['grades'] = []