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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def lilypond(point):
 """ Generate lilypond representation for a point """

    #If lilypond already computed, leave as is
    if "lilypond" in point:
        return point

    #Defaults:
    pitch_string = ""
    octave_string = ""
    duration_string = ""
    preamble = ""
    dynamic_string = ""
    if "pitch" in point:
        octave = point["octave"]
        pitch = point["pitch"]
        if octave > 4:
            octave_string = "'" * (octave - 4)
        elif octave < 4:
            octave_string = "," * (4 - octave)
        else:
            octave_string = ""
        m = modifiers(pitch)
        if m > 0:
            modifier_string = "is" * m
        elif m < 0:
            modifier_string = "es" * -m
        else:
            modifier_string = ""
        pitch_string = letter(pitch).lower() + modifier_string

    if DURATION_64 in point:
        duration = point[DURATION_64]
        if duration > 0:
            if duration % 3 == 0:  # dotted note
                duration_string = str(192 // (2 * duration)) + "."
            else:
                duration_string = str(64 // duration)
        #TODO: for now, if we have a duration but no pitch, show a 'c' with an x note
        if duration_string:
            if not pitch_string:
                pitch_string = "c"
                octave_string = "'"
                preamble = r'\xNote '

    if "dynamic" in point:
        dynamic = point["dynamic"]
        if dynamic == "crescendo":
            dynamic_string = "\<"
        elif dynamic == "diminuendo":
            dynamic_string = "\>"
        else:
            dynamic_string = "\%s" % (dynamic,)

    point["lilypond"] = "%s%s%s%s%s" % (preamble, pitch_string, octave_string, duration_string, dynamic_string)

    return point