Excel Power Query - checking date in a list of dates using M

I have to compare if a date in table A is present in all of the dates column in table B, return 1 if yes and no otherwise. I am using Excel Power Query and my formula is this:

Table.AddColumn(#"Renamed Columns", "BL_Count", each if List.Contains(Dates[Dates_WeekStart],[BL_WeekStart]) then 1 else 0)

I get all as 0s though. What am I doing wrong?

Dates table has all weekStart dates from 2015 onwards. There is no other column in that table. BL_WeekStart has various WeekStart values, I need to compare if that date is present in Dates and return a 1.