how to access a data within a list of a list code example

Example 1: a list inside a list python

board = []    
for i in range(6): # create a list with nested lists
    board.append([])
    for n in range(6):
        board[i].append("O") # fills nested lists with data

Example 2: python index list in list

>>> list1 = [[10,13,17],[3,5,1],[13,11,12]]
>>> list1[0][2]
17