def comma(array):
    count = len(array)
    stringpos = int((count - 1))
    array.insert(stringpos,'and')
    for i in range(len(array)-2):
        array[i] = array[i] + ','
    for i in range(len(array)):
        print(array[i],end=" ")

spam = ['cat', 'elephant', 'dog', 'beast', 'test', 'jake', 'boo boo', 'anna']
comma(spam)