input: Write a function to read an array from the user and then determine the mean and median of the array. 
  
  def mean_median(arr):
        arr_sum = 0
        for i in range(len(arr)):
              arr_sum += arr[i]
        
        mean = arr_sum/len(arr)
        
        arr = sorted(arr)
        if len(arr) % 2 != 0:
              median = arr[len(arr)//2]
        else:
              median = (arr[len(arr)//2] + arr[len(arr)//2 - 1]) / 2
        
        return mean, median
  
  assert mean_median([10, 15, 20, 25, 30, 35])==(22.5, 22.5)
  assert mean_median([1, 2, 3, 4, 5])==(3.0, 3)
  assert mean_median([5, 3, 1, 4, 2])==(3.0, 3)
output: def mean_median(arr):
        arr_sum = 0
        for i in range(len(arr)):
              arr_sum += arr[i]
        
        mean = arr_sum/len(arr)
        
        arr = sorted(arr)
        if len(arr) % 2 != 0:
              median = arr[len(arr)//2]
        else:
              median = (arr[len(arr)//2] + arr[len(arr)//2 - 1]) / 2
        
        return mean, median