Create a new DB snapshot.

        :type snapshot_id: string
        :param snapshot_id: The identifier for the DBSnapshot

        :type dbinstance_id: string
        :param dbinstance_id: The source identifier for the RDS instance from
                              which the snapshot is created.

        :rtype: :class:`boto.rds.dbsnapshot.DBSnapshot`
        :return: The newly created DBSnapshot

def create_dbsnapshot(self, snapshot_id, dbinstance_id):
        """
        Create a new DB snapshot.

        :type snapshot_id: string
        :param snapshot_id: The identifier for the DBSnapshot

        :type dbinstance_id: string
        :param dbinstance_id: The source identifier for the RDS instance from
                              which the snapshot is created.

        :rtype: :class:`boto.rds.dbsnapshot.DBSnapshot`
        :return: The newly created DBSnapshot
        """
        params = {'DBSnapshotIdentifier' : snapshot_id,
                  'DBInstanceIdentifier' : dbinstance_id}
        return self.get_object('CreateDBSnapshot', params, DBSnapshot)