input: 
  from typing import List, Optional
  
  def auto_complete(dictionary: List[str], prefix: str) -> Optional[List[str]]:
      """Generates a list of words from the dictionary that start with the given prefix.
      If no words match the prefix, it returns None.
      
      Example:
      >>> auto_complete(["dog", "deer", "deal", "dungeon", "dark", "dusk"], "d")
      ['dog', 'deer', 'deal', 'dungeon', 'dark', 'dusk']
      >>> auto_complete(["cat", "bat", "car"], "d")
      None
      """
      prefix_words = [word for word in dictionary if word.startswith(prefix)]
      return prefix_words or None
  
  # Test cases
  dictionary = ["dog", "deer", "deal", "dungeon", "dark", "dusk"]
  prefix = "d"
  prefix_words = auto_complete(dictionary, prefix)
  print(prefix_words)  # Output: ['dog', 'deer', 'deal', 'dungeon', 'dark', 'dusk']
  
  dictionary = ["cat", "bat", "car"]
  prefix = "d"
  prefix_words = auto_complete(dictionary, prefix)
  print(prefix_words)  # Output: None
  
output:     
      prefix_words = [word for word in dictionary if word.startswith(prefix)]
      return prefix_words or None
  