input: Write a function to print out the largest value from a given list of numbers.
  
  def get_max_value(numbers): 
      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([8])==8
  assert get_max_value([3, 3, 3, 3])==3
  assert get_max_value([])==None
output: def get_max_value(numbers): 
      if not numbers:
          return None
      return max(numbers)