input: Write a function to find the most frequent number in a list.
  assert most_frequent([1, 2, 3, 4, 4, 3, 3, 3]) == 3
  assert most_frequent([10, 20, 10, 30, 10, 40, 10, 50]) == 10
  assert most_frequent([5, 5, 5, 2, 2, 2, 3, 3, 3]) == 5
output: def most_frequent(numbers):
      from collections import Counter
      count = Counter(numbers)
      return count.most_common(1)[0][0]