input: Write a function to find and print the largest value from a given list of numbers. If the list is empty, the function should 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([7, 3, 9, 5]) == 9
  assert get_max_value([10]) == 10
  assert get_max_value([]) == None
output: def get_max_value(numbers):
      if not numbers:
          return None
      return max(numbers)