input: def create_song_class(title: str, artist: str) -> Song:
      """ Create a Song class with title and artist as instance variables, and 
      str(), eq(), and length() as methods.
      >>> s1 = create_song_class("Bohemian Rhapsody", "Queen")
      >>> print(s1)
      Title: Bohemian Rhapsody
      Artist: Queen
      >>> s2 = create_song_class("Bohemian Rhapsody", "Queen")
      >>> s1 == s2
      True
      >>> s1.length()
      16
      """
      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)
      return Song(title, artist)
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)
      return Song(title, artist)