Exercise 1: Dedupe a List, Preserving Order — Possible Solution
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words_list = ["who", "why", "when", "who", "when",
              "what", "where", "whom", "who", "when", "who"]

new_list = []
index = 0

while index < len(words_list):
    new_index = 0
    found = False

    while new_index < len(new_list):
        if words_list[index] == new_list[new_index]:
            found = True
            break
        new_index += 1

    if not found:
        new_list.append(words_list[index])

    index += 1

print(new_list)

Output:
['who', 'why', 'when', 'what', 'where', 'whom']

WHY THIS WORKS AS AN ANSWER
------------------------------
The structure is identical to the lesson's tuple case study — an outer
while walking words_list by index, an inner while searching new_list
for a match, and a found flag deciding whether to add the current word.
The only real difference is the last line of the "add it" branch:
new_list.append(words_list[index]) instead of tuple concatenation,
because lists are mutable and have a real .append() method. Both the
outer index and the inner new_index are incremented unconditionally
every time their own loop runs, which is exactly what keeps both loops
from spinning forever.