input: Write a python function to calculate the mean, median, and mode of a list of numbers.
  assert calculate_statistics([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]) == (8, 8, [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15])
  assert calculate_statistics([1, 2, 2, 3, 4, 5]) == (2.8333333333333335, 2, [2])
  assert calculate_statistics([1, 1, 2, 2, 3, 3]) == (2.0, 2, [1, 2, 3])
output: from collections import Counter
  import statistics
  
  def calculate_statistics(numbers):
      mean = statistics.mean(numbers)
      median = statistics.median(numbers)
      mode_data = Counter(numbers)
      max_count = max(mode_data.values())
      mode = [k for k, v in mode_data.items() if v == max_count]
      return mean, median, mode