input: Write a python function to find the most common elements in a list.
  assert most_common([1, 3, 2, 1, 2, 3, 3]) == [3]
  assert most_common([4, 4, 1, 2, 2, 3, 4, 2, 2]) == [2]
  assert most_common([1, 2, 3, 4, 5]) == [1, 2, 3, 4, 5]
output: def most_common(lst):
      from collections import Counter
      count = Counter(lst)
      max_freq = max(count.values())
      return [item for item, freq in count.items() if freq == max_freq]