array = [["A",6],
        ["H",3],
        ["C",7],
        ["E",4],
        ["L",5],
        ["L",8],
        ["B",2],
        ["D",None],
        ["O",None],
        [None,None]]

def traverse(array):
    #change pointer from 0 to 1 to see different linked lists
    pointer = 0
    while pointer != None:
        node = array[pointer]
        data = node[0]
        print(data)
        pointer = node[1]

traverse(array)