input: from typing import Tuple, Union
  
  def find_closest_pair(numbers: Tuple[float, ...]) -> Union[Tuple[float, float], None]:
      """ Finds the two closest numbers in a list of numbers and returns them as a tuple.
      If there's a tie, return the first pair that is closest.
      If the input list has fewer than 2 numbers, return None.
      >>> find_closest_pair((1.0, 2.0, 3.0, 4.0))
      (1.0, 2.0)
      >>> find_closest_pair((15.0, 12.1, 13.5, 14.8, 19.0))
      (14.8, 15.0)
      >>> find_closest_pair((8.0,))
      None
      """
output:     if len(numbers) < 2:
          return None
      
      closest_pair = None
      min_distance = float('inf')
      
      for i in range(len(numbers)):
          for j in range(i + 1, len(numbers)):
              distance = abs(numbers[i] - numbers[j])
              if distance < min_distance:
                  min_distance = distance
                  closest_pair = (numbers[i], numbers[j])
      
      return closest_pair