input: Write a function to read an array from the user and then determine the mean and median of the array. Use the function to print the mean and median of the input array.
  assert mean_median([10, 15, 20, 25, 30, 35])==(22.5, 22.5)
  assert mean_median([10, 20, 30])==(20.0, 20.0)
  assert mean_median([11, 13, 15, 17, 19])==(15.0, 15)
  assert mean_median([1, 2, 3, 4])==(2.5, 2.5)
  assert mean_median([5])==(5.0, 5)
output: def mean_median(arr):
      arr.sort()
      n = len(arr)
      mean = sum(arr) / n
      if n % 2 == 0:
          median = (arr[n//2 - 1] + arr[n//2]) / 2
      else:
          median = arr[n//2]
      return (mean, median)