1class Tone:
  2    CHROMATIC_SCALE = ("C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B")
  3
  4    def __init__(self, name):
  5        self.name = name
  6        self.index = self.CHROMATIC_SCALE.index(name)
  7
  8    def __str__(self):
  9        return self.name
 10    
 11    def __eq__(self, other):
 12        return self.name == other.name
 13    
 14    def __hash__(self):
 15        return hash(self.name)
 16    
 17    def __add__(self, other):
 18        """Add Tone and Tone or Tone and Interval"""
 19        if isinstance(other, Tone):
 20            return Chord(self, other)
 21        if isinstance(other, Interval):
 22            return Tone(self.CHROMATIC_SCALE[(self.index + other.semitones) % 12])
 23    
 24    def __sub__(self, other):
 25        """Substract Tone from Tone or Tone from Interval"""
 26        if isinstance(other, Tone):
 27            return Interval((self.index - other.index) % 12)
 28        if isinstance(other, Interval):
 29            return Tone(self.CHROMATIC_SCALE[(self.index - other.semitones) % 12])
 30
 31    
 32
 33class Interval:
 34    INTERVAL_NAMES = (
 35        "unison",
 36        "minor 2nd",
 37        "major 2nd",    
 38        "minor 3rd",
 39        "major 3rd",
 40        "perfect 4th",
 41        "diminished 5th",
 42        "perfect 5th",
 43        "minor 6th",
 44        "major 6th",
 45        "minor 7th",
 46        "major 7th"
 47    )
 48
 49    def __init__(self, semitones):
 50        self.semitones = semitones % 12
 51
 52    def __str__(self):
 53        return self.INTERVAL_NAMES[self.semitones % 12]
 54    
 55    def __add__(self, other):
 56        """Throw err when adding Interval and Tone; Add Interval and Interval"""
 57        if isinstance(other, Tone):
 58            raise TypeError("Invalid operation")
 59        if isinstance(other, Interval):
 60            return Interval((self.semitones + other.semitones) % 12)
 61        
 62    def __sub__(self, other):
 63        """Throw err when substracting Tone from Interval"""
 64        if isinstance(other, Tone):
 65            raise TypeError("Invalid operation")
 66        
 67    def __neg__(self):
 68        return Interval(-self.semitones)
 69    
 70
 71class Chord:
 72    def __init__(self, root, *tones):
 73        unique_tones = {root, *tones}
 74        if len(unique_tones) < 2:
 75            raise TypeError("Cannot have a chord made of only 1 unique tone")
 76        self.root = root
 77        self.tones = sorted(unique_tones, key=lambda tone: (tone.index - root.index) % 12)
 78
 79    def __str__(self):
 80        return "-".join(str(t) for t in self.tones)
 81    
 82    def is_minor(self):
 83        """Has minor 3rd"""
 84        return any((t.index - self.root.index) % 12 == 3 for t in self.tones)
 85    
 86    def is_major(self):
 87        """Has major 3rd"""
 88        return any((t.index - self.root.index) % 12 == 4 for t in self.tones)
 89    
 90    def is_power_chord(self):
 91        """Is not minor and major"""
 92        return not (self.is_minor() or self.is_major())
 93    
 94    def __sub__(self, other):
 95        """Substract Tone from Chord"""
 96        if isinstance(other, Tone):
 97            if other not in self.tones:
 98                raise TypeError(f"Cannot remove tone {other} from chord {self}")
 99            new_tones = [tone for tone in self.tones if tone != other]
100            if len(new_tones) < 2:
101                raise TypeError("Cannot have a chord made of only 1 unique tone")
102            if other == self.root:
103                new_root = new_tones[0]
104                return Chord(new_root, *new_tones)
105            return Chord(self.root, *new_tones)
106        
107    def __add__(self, other):
108        """Add Chord and Tone or Chord and Chord"""
109        if isinstance(other, Tone):
110            self.tones.append(other)
111            unique_tones = {self.root, *self.tones}
112            self.tones = sorted(unique_tones, key=lambda tone: (tone.index - self.root.index) % 12)
113            return Chord(self.root, *self.tones)
114        if isinstance(other, Chord):
115            tones_sum = {self.root, *self.tones, *other.tones}
116            return Chord(self.root, *tones_sum)
117        
118    def transposed(self, interval):
119        """Move with interval positions each tone in the chord"""
120        transposed_tones = [tone + interval for tone in self.tones]
121        return Chord(transposed_tones[0], *transposed_tones)