input: def create_song_class(title: str, artist: str) -> Song:
      """Create a Python class Song with two instance variables, title and artist, 
      and three methods, str(), eq(), and length().
      >>> song1 = create_song_class("Bohemian Rhapsody", "Queen")
      >>> str(song1)
      'Title: Bohemian Rhapsody\\nArtist: Queen'
      >>> song2 = create_song_class("Bohemian Rhapsody", "Queen")
      >>> song1 == song2
      True
      >>> song3 = create_song_class("Stairway to Heaven", "Led Zeppelin")
      >>> song1 == song3
      False
      >>> song1.length()
      17
      """
output:     
      class Song:
          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: object) -> bool:
              if isinstance(other, Song):
                  return self.title == other.title and self.artist == other.artist
              return False
          
          def length(self) -> int:
              return len(self.title) + len(self.artist)
      
      return Song(title, artist)
  