input: 
  from typing import List
  from collections import Counter
  
  def frequent_words(words: List[str], n: int) -> List[str]:
      """Returns a list of words that appear at least n times in the given list of words.
      >>> frequent_words(['a', 'b', 'a', 'c', 'd', 'a', 'x', 'd', 'd'], 3)
      ['a', 'd']
      >>> frequent_words(['hello', 'world', 'hello'], 2)
      ['hello']
      """
      counts = Counter(words)
      return [word for word, count in counts.items() if count >= n]
  
output:     counts = Counter(words)
      return [word for word, count in counts.items() if count >= n]