Restore descriptor rom BigQuery

def restore_descriptor(self, converted_descriptor):
        """Restore descriptor rom BigQuery
        """

        # Convert
        fields = []
        for field in converted_descriptor['fields']:
            field_type = self.restore_type(field['type'])
            resfield = {
                'name': field['name'],
                'type': field_type,
            }
            if field.get('mode', 'NULLABLE') != 'NULLABLE':
                resfield['constraints'] = {'required': True}
            fields.append(resfield)
        descriptor = {'fields': fields}

        return descriptor