input: Write a python function to calculate the median of a list of numbers.
  assert calculateMedian([2, 4, 3, 5, 7])==4
  assert calculateMedian([1, 2, 3, 4, 5, 6])==3.5
  assert calculateMedian([10, 20, 30, 40, 50])==30
output: def calculateMedian(numbers):
      numbers.sort()
      n = len(numbers)
      mid = n // 2
      if n % 2 == 0:
          return (numbers[mid - 1] + numbers[mid]) / 2
      else:
          return numbers[mid]