Count elements in a list python

Question

I need to be able to count how many of the string \"O\" is in my list

top_board = [
    [None, None, None, None, None, None, None, None, None],
    [None, None,         


        

Answer 1

if [j for i in top_board for j in i].count('O'):
    print "O is present in the list"