input: Write a function to determine if it is possible to create a Python class Song that matches the specified criteria, where the class contains two instance variables (title and artist) and three methods (`__str__`, `__eq__`, and `length`). If it is possible, return True; otherwise, return False. If the input is not valid, return False.
  assert create_song_class({}) == True
  assert create_song_class({'title': 'Let It Be', 'artist': 'The Beatles'}) == True
  assert create_song_class({'title': 123, 'artist': 'The Beatles'}) == False
  assert create_song_class({'title': 'Hey Jude', 'artist': ''}) == True
  assert create_song_class(None) == False
output: def create_song_class(input_dict):
      if not isinstance(input_dict, dict):
          return False
      if 'title' not in input_dict or 'artist' not in input_dict:
          return False
      if not isinstance(input_dict['title'], str) or not isinstance(input_dict['artist'], str):
          return False
      return True