divide list ['a', 'b', 'c', '1', '2', '3'] into three separate list

def split(list):
    list1 = []
    list2 = []
    list3 = []
    for i in range(len(list)):
        if i < len(list)//3:
            list1.append(list[i])
        elif i < len(list) * 2 // 3:
            list2.append(list[i])
        else:
            list3.append(list[i])
    return list1, list2, list3

split(['a', 'b', 'c', '1', '2', '3'])