input: Write a python function to calculate the mean, median, and mode of a list of numbers.
  assert mean([1, 2, 3, 4, 5]) == 3.0
  assert median([1, 2, 3, 4, 5]) == 3
  assert mode([1, 2, 3, 4, 4, 5]) == 4
  assert mean([1, 2, 2, 3, 4]) == 2.4
  assert median([1, 2, 3, 4]) == 2.5
  assert mode([1, 1, 2, 3, 3]) == 1
output: def mean(numbers):
      return sum(numbers) / len(numbers)
  
  def median(numbers):
      numbers.sort()
      n = len(numbers)
      if n % 2 == 1:
          return numbers[n // 2]
      else:
          mid1, mid2 = numbers[n // 2 - 1], numbers[n // 2]
          return (mid1 + mid2) / 2
  
  def mode(numbers):
      from collections import Counter
      count = Counter(numbers)
      max_freq = max(count.values())
      mode_list = [k for k, v in count.items() if v == max_freq]
      return min(mode_list)