list inside a list in python

1board = []    
2for i in range(6): # create a list with nested lists
3    board.append([])
4    for n in range(6):
5        board[i].append("O") # fills nested lists with data

1# it appends a list into a list
2list1 = [1,2,3,4,5]
3list1.append([6,7])
4# ouput = [1, 2, 3, 4, 5, [6, 7]]

1board = []    
2for i in range(6): # create a list with nested lists
3    board.append([])
4    for n in range(6):
5        board[i].append("O") # fills nested lists with data
6