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