input: Write a function to validate if a class named `Song` is correctly implemented based on the given criteria. The class should have two instance variables `title` and `artist`, and three methods `__str__()`, `__eq__()`, and `length()`. The `__str__()` method should return a formatted string with the title and artist, the `__eq__()` method should compare two Song objects based on their title and artist, and the `length()` method should return the length of the title. The function should return True if the class definition meets the criteria, otherwise False.
  
  
  def validate_song_class(SongClass):
      song1 = SongClass("Bohemian Rhapsody", "Queen")
      song2 = SongClass("Bohemian Rhapsody", "Queen")
      song3 = SongClass("Hotel California", "Eagles")
  
      assert str(song1) == 'Title: Bohemian Rhapsody\nArtist: Queen'
      assert song1 == song2
      assert song1 != song3
      assert song1.length() == len("Bohemian Rhapsody")
  
      return True
  
  # Example usage:
  class ValidSong:
      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 validate_song_class(ValidSong) == True
  
output: def validate_song_class(SongClass):
      song1 = SongClass("Bohemian Rhapsody", "Queen")
      song2 = SongClass("Bohemian Rhapsody", "Queen")
      song3 = SongClass("Hotel California", "Eagles")
  
      if str(song1) != 'Title: Bohemian Rhapsody\nArtist: Queen':
          return False
      if song1 != song2:
          return False
      if song1 == song3:
          return False
      if song1.length() != len("Bohemian Rhapsody"):
          return False
  
      return True