'Delete an existing DBInstance.
:type id: str
:param id: Unique identifier for the new instance.
:type skip_final_snapshot: bool
:param skip_final_snapshot: This parameter determines whether a final
db snapshot is created before the instance
is deleted.  If True, no snapshot
is created.  If False, a snapshot
is created before deleting the instance.
:type final_snapshot_id: str
:param final_snapshot_id: If a final snapshot is requested, this
is the identifier used for that snapshot.
:rtype: :class:`boto.rds.dbinstance.DBInstance`
:return: The deleted db instance.'

def delete_dbinstance(self, id, skip_final_snapshot=False, final_snapshot_id=''):

    params = {'DBInstanceIdentifier': id}
    if skip_final_snapshot:
        params['SkipFinalSnapshot'] = 'true'
    else:
        params['SkipFinalSnapshot'] = 'false'
        params['FinalDBSnapshotIdentifier'] = final_snapshot_id
    return self.get_object('DeleteDBInstance', params, DBInstance)
