EXCEPT function - MDX

WITH
MEMBER [Leave Type].[Leave Type].[MyType] AS
AGGREGATE(EXCEPT([Leave Type].[Leave Type].[Leave Type].MEMBERS,
{
[Leave Type].[Leave Type].&[53] -- OnDuty
,[Leave Type].[Leave Type].&[61] -- OptionalHoliday
,[Leave Type].[Leave Type].&[62] -- NoAccessCard
}))
, FORMAT_STRING = "#,##0.0"

SELECT [Measures].[Leave Count] ON 0
, [Leave Type].[Leave Type].[MyType] ON 1
FROM [Resource Utilization]