Python 3 kodunu anlamadım

def almostIncreasingSequence(sequence):

    droppped = False

    last = prev = min(sequence) - 1

    for elm in sequence:

        if elm <= last:

            if droppped:

                return False

            else:

                droppped = True

            if elm <= prev:

                prev = last

            elif elm >= prev:

                prev = last = elm

        else:

            prev, last = last, elm

    return True