input: Write a function to print out the largest value from a given list of numbers. If the list is empty, return None.
  
  def get_max_value(numbers): 
      if not numbers:
          return None
      return max(numbers)
  
  assert get_max_value([2, 4, 1, 6]) == 6
  assert get_max_value([-1, -4, -2, -6]) == -1
  assert get_max_value([]) == None
  assert get_max_value([0, 0, 0, 0]) == 0
output: def get_max_value(numbers): 
      if not numbers:
          return None
      return max(numbers)