Prior year forecast Dax.

PY Full Year Forecast = Calculate(

[Report],
FILTER (
GL,
GL[v] = {"Prior Forecast"}
),
Filter(
'Date',
'Date'[Year]= [Selected Year]-1
)

)

tables have GL which has version  , data and date  as column . data shows the number and version points like like FY , PY , prior year forecast, now i need to calculate full year peior forecast , what could be the Dax for that.