MDX script that calculates the base of the measure on the value of the dimension attribute member

What's new in the MDX scripts and I'm trying to create a calculated measure that calculates the price base in the package type. Using this mdx script, I return 0 in total in Excel connected to the analysis database.

with MEMBER [Measures].[Price] AS
WHEN [Product].[Package].CURRENTMEMBER.member_key = "S"
so [Qty]* 150
WHEN [Product].[Package].CURRENTMEMBER.member_key = "M"
so [Qty]* 300
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