input: Write a function to find the median of a list of numbers.
  assert find_median([1, 3, 3, 6, 7, 8, 9]) == 6
  assert find_median([1, 2, 3, 4, 5, 6, 8, 9]) == 4.5
  assert find_median([10, 20, 30, 40, 50]) == 30
  assert find_median([11, 23, 58, 92, 100, 120]) == 75
  assert find_median([4, 8, 15, 16, 23, 42]) == 15.5
output: def find_median(numbers):
      numbers.sort()
      n = len(numbers)
      if n % 2 == 0:
          median = (numbers[n//2 - 1] + numbers[n//2]) / 2
      else:
          median = numbers[n//2]
      return median