input: Write a function to get the maximum and minimum values in a given list.
  def get_max_min(lst):
   min_value = lst[0]
   max_value = lst[0]
   
   for i in range(1, len(lst)):
    if lst[i] > max_value:
     max_value = lst[i]
    if lst[i] < min_value:
     min_value = lst[i]
   
   return (min_value, max_value)
  
  assert get_max_min([3, 4, 5, 1, 2])==(1, 5)
  assert get_max_min([3, 5, 10, 1, 2])==(1, 10)
  assert get_max_min([4, 3, 1, 2])==(1, 4)
  assert get_max_min([3, 5, 4, 1, 2])==(1, 5)
  assert get_max_min([])==(None, None)
output: def get_max_min(lst):
      if not lst:
          return (None, None)
      min_value = lst[0]
      max_value = lst[0]
      
      for i in range(1, len(lst)):
          if lst[i] > max_value:
              max_value = lst[i]
          if lst[i] < min_value:
              min_value = lst[i]
      
      return (min_value, max_value)