Use ReturnValues if you want to get the item attributes as they appeared before they were deleted. For DeleteItem, the valid values are:
NONE - If ReturnValues is not specified, or if its value is NONE, then
nothing is returned. (This setting is the default for ReturnValues.)
ALL_OLD - The content of the old item is returned. The ReturnValues parameter is used by several DynamoDB operations; however,
DeleteItem does not recognize any values other than NONE or ALL_OLD.