input: 
  from typing import Optional
  
  class Song:
      """ A class representing a song with a title and artist. Provides str() and eq() methods for easy string 
      representation and comparison, as well as a length() method that returns the length of the title.
      
      >>> song1 = Song("Bohemian Rhapsody", "Queen")
      >>> song2 = Song("Bohemian Rhapsody", "Queen")
      >>> song3 = Song("Hotel California", "Eagles")
      >>> print(song1)
      Title: Bohemian Rhapsody
      Artist: Queen
      >>> song1 == song2
      True
      >>> song1 == song3
      False
      >>> song1.length()
      16
      """
      def __init__(self, title: str, artist: str):
          self.title = title
          self.artist = artist
    
      def __str__(self) -> str:
          return f'Title: {self.title}\nArtist: {self.artist}'
      
      def __eq__(self, other: Optional['Song']) -> bool:
          if not isinstance(other, Song):
              return False
          return self.artist == other.artist and self.title == other.title
  
      def length(self) -> int:
          return len(self.title)
  
output:     def __init__(self, title: str, artist: str):
          self.title = title
          self.artist = artist
    
      def __str__(self) -> str:
          return f'Title: {self.title}\nArtist: {self.artist}'
      
      def __eq__(self, other: Optional['Song']) -> bool:
          if not isinstance(other, Song):
              return False
          return self.artist == other.artist and self.title == other.title
  
      def length(self) -> int:
          return len(self.title)