input: Write a function to create a class in Python that meets the specified requirements. The class should be named `Song` and have two instance variables, `title` and `artist`. It should also include three methods: `__str__()`, which returns a formatted string with the title and artist; `__eq__()`, which compares two instances of `Song` based on their title and artist; and `length()`, which returns the length of the title.
  
  
  class Song:
      def __init__(self, title, artist):
          self.title = title
          self.artist = artist
    
      def __str__(self):
          return f'Title: {self.title}\nArtist: {self.artist}'
      
      def __eq__(self, other):
          return self.artist == other.artist and self.title == other.title
  
      def length(self):
          return len(self.title)
  
  
  assert str(Song('Bohemian Rhapsody', 'Queen')) == 'Title: Bohemian Rhapsody\nArtist: Queen'
  assert Song('Bohemian Rhapsody', 'Queen') == Song(title='Bohemian Rhapsody', artist='Queen')
  assert Song('Bohemian Rhapsody', 'Queen') != Song('We Will Rock You', 'Queen')
  assert Song('Bohemian Rhapsody', 'Queen').length() == 16
  assert Song('Halo', 'Beyonce').length() == 4
output: class Song:
      def __init__(self, title, artist):
          self.title = title
          self.artist = artist
    
      def __str__(self):
          return f'Title: {self.title}\nArtist: {self.artist}'
      
      def __eq__(self, other):
          return self.artist == other.artist and self.title == other.title
  
      def length(self):
          return len(self.title)