DAX filter

hello, I wrote a DAX code to retrieve only the positive lines of my subtraction.
but there is a problem I am told to include a parameter in the ALLSELECTED(),

Positive Result =
CALCULATE (
[Sum Measure 1] - [Sum Measure 2],
FILTER (
ALLSELECTED ( ),
[Sum Measure 1] - [Sum Measure 2] > 0
)
)

THANKS