If a cell contains any of these values, then label as this

I want to set up a formula in Excel so if column A (which contains dates) contains any of the dates in a list of 7 dates, then it will be labeled as "Week 1", but if not, it'll be labeled as "Week 2". The formula listed below is returning #NAME error. Any thoughts?

ie:

Column A Column B 9/1/15 9/1/15 9/12/15 9/2/15 9/24/15 9/3/15 9/8/15 9/4/15 9/2/15 9/5/15 9/3/15 9/6/15 9/19/15 9/9/15

=IF((A1,containsAny=B1:b7), "Week 1", "Week 2")