input: 
  def create_song_class():
      """ Creates a class in Python with the specified criteria.
      >>> song1 = Song("Bohemian Rhapsody", "Queen")
      >>> song2 = Song("Stairway to Heaven", "Led Zeppelin")
      >>> str(song1)
      'Title: Bohemian Rhapsody\nArtist: Queen'
      >>> song1 == song2
      False
      >>> song1.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
  
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