input: Write a python function to find the most frequent element in a list.
  assert most_frequent([1, 3, 1, 3, 2, 1]) == 1
  assert most_frequent([4, 5, 4, 6, 4, 7]) == 4
  assert most_frequent([10, 20, 30, 10, 10, 20, 30, 10, 30, 30, 30]) == 30
output: def most_frequent(lst):
      from collections import Counter
      count = Counter(lst)
      return count.most_common(1)[0][0]