input: Write a function to take a list of words and an integer n, and return a list of words that appear at least n times in the given list. Use the Counter class from the collections module to count the occurrences of each word.
  assert frequent_words(['a', 'b', 'a', 'c', 'd', 'a', 'x', 'd', 'd'], 3)==['a', 'd']
  assert frequent_words(['x', 'x', 'y', 'z', 'z', 'x', 'y', 'y', 'z'], 2)==['x', 'y', 'z']
  assert frequent_words(['q', 'w', 'e', 'r', 't', 'y'], 2)==[]
  assert frequent_words([], 1)==[]
  assert frequent_words(['a', 'a', 'a'], 1)==['a']
output: from collections import Counter
  
  def frequent_words(words, n):
      word_counts = Counter(words)
      return [word for word, count in word_counts.items() if count >= n]