How to deal with polynomials

poly.py

def addPoly(a: list, b: list):
    index_a = 0
    index_b = 0

    len_a = len(a)
    len_b = len(b)

    result = []

    while True:
        pick_from_a = a[index_a] if index_a < len_a else None
        pick_from_b = b[index_b] if index_b < len_b else None

        if pick_from_a is None and pick_from_b is None:
            return result

        if pick_from_a is None:
            result.append(pick_from_b)
            index_b += 1
        elif pick_from_b is None:
            result.append(pick_from_a)
            index_a += 1
        else:
            if pick_from_a[0] > pick_from_b[0]:
                result.append(pick_from_a)
                index_a += 1
            elif pick_from_a[0] < pick_from_b[0]:
                result.append(pick_from_b)
                index_b += 1
            else:
                result.append([pick_from_a[0], pick_from_a[1] + pick_from_b[1]])
                index_a += 1
                index_b += 1


def multiplyPoly(a: list, b: list):
    # 한줄솔루션
    # return list(map(lambda exp: [exp, sum(map(lambda term: term[1], filter(lambda term: term[0] == exp, [[from_a[0] + from_b[0], from_a[1] * from_b[1]] for from_a in a for from_b in b])))], sorted(list(set(map(lambda term: term[0], [[from_a[0] + from_b[0], from_a[1] * from_b[1]] for from_a in a for from_b in b]))), reverse=True)))

    result = []

    for pick_from_a in a:
        for pick_from_b in b:
            result.append([
                pick_from_a[0] + pick_from_b[0],  # 지수는 더하구
                pick_from_a[1] * pick_from_b[1]  # 계수는 곱하구
            ])

    return list(map(lambda exp: [exp, sum(map(lambda term: term[1], filter(lambda term: term[0] == exp, result)))], sorted(list(set(map(lambda term: term[0], result))), reverse=True)))


if __name__ == '__main__':
    print(
        addPoly(
            [[5, 3], [3, 5], [1, 4], [0, 2]],
            [[5, 2], [2, 4], [1, 3]]
        )
    )

    print(
        multiplyPoly(
            [[5, 3], [3, 5], [1, 4], [0, 2]],
            [[5, 2], [2, 4], [1, 3]]
        )
    )