调优程序：NameError：名称'self'未定义

Question

运行以下课程时，我得到NameError: name 'self' is not defined。发生了什么，我该如何解决？

class Tuner():
    def __init__(self, key=-1, notelist=[[0, 4]]):
        """
        Takes a list of 2-element lists containing a note and its 8ve,
        then finds the equal-tempered frequency of each note,
        appending this frequency to a new list 'freqlist'
        """
        #if key != -1:
        key = inputkey()
        print key
        #if notelist != [[0, 4]]:
        notelist = inputnotes()

        freqs_equal = []
        for note in notelist:
            letter = note[0]
            octave = note[1]
            freq = 440 * ((2 ** (1.0/12.0)) ** (letter - 9 - (12 * 4)))
            if octave != 0:
                freq = freq * ((2 ** (1.0/12.0)) ** (octave * 12))
            freqs_equal.append(freq)

        freqs_just = []
        for note in notelist:
            letter = note[0]
            octave = note[1]  # get the note's name and octave
            if letter - key >= 0:
                interval = letter - key
            else:
                interval = (letter + 12) - key
                octave -= 1

            keyfreq = 440 * ((2 ** (1.0/12.0)) ** (key - 9 - (12 * 4)))
            letterfreq = keyfreq * justratios[interval]
            letterfreq = letterfreq * (2 ** octave)
            freqs_just.append(letterfreq)

        self.freqs_equal = freqs_equal
        self.freqs_just = freqs_just