input: Write a function to find the most frequent element in a list using the Counter class from the collections module.
  assert most_frequent([1, 3, 3, 3, 5, 4, 4, 6]) == 3
  assert most_frequent([10, 20, 10, 30, 30, 30]) == 30
  assert most_frequent([7, 8, 9, 7, 8, 7, 8]) == 7
output: def most_frequent(lst):
      from collections import Counter
      counter = Counter(lst)
      most_common_element = counter.most_common(1)[0][0]
      return most_common_element