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, 2, 3, 4]) == [2]
  assert mean([10, 20, 30, 40, 50]) == 30.0
  assert median([1, 2, 3, 4, 5, 6]) == 3.5
  assert mode([10, 10, 20, 20, 30]) == [10, 20]
output: from collections import Counter
  
  def mean(numbers):
      return sum(numbers) / len(numbers)
  
  def median(numbers):
      sorted_numbers = sorted(numbers)
      n = len(sorted_numbers)
      mid = n // 2
      if n % 2 == 0:
          return (sorted_numbers[mid - 1] + sorted_numbers[mid]) / 2
      else:
          return sorted_numbers[mid]
  
  def mode(numbers):
      count = Counter(numbers)
      max_freq = max(count.values())
      return sorted([num for num, freq in count.items() if freq == max_freq])