Check if something is (not) in a list in Python

I have a list of tuples in Python, and I have a conditional where I want to take the branch ONLY if the tuple is not in the list (if it is in the list, then I don’t want to take the if branch)

if curr_x -1 > 0 and (curr_x-1 , curr_y) not in myList: 

    # Do Something

This is not really working for me though. What have I done wrong?