input: def organize_numbers(numbers):
      """
      When provided with a list of non-negative integers, generate a new list where the integers are sorted,
      arranging them in increasing order if the sum of the first and last elements is odd,
      or in decreasing order if the sum of the first and last elements is even.
  
      Important:
      * The input list should remain unaltered.
  
      Examples:
      * organize_numbers([]) => []
      * organize_numbers([5]) => [5]
      * organize_numbers([2, 4, 3, 0, 1, 5]) => [0, 1, 2, 3, 4, 5]
      * organize_numbers([2, 4, 3, 0, 1, 5, 6]) => [6, 5, 4, 3, 2, 1, 0]
      """
output:     
      if not numbers:
          return []
      
      if (numbers[0] + numbers[-1]) % 2 == 0:
          return sorted(numbers, reverse=True)
      else:
          return sorted(numbers)
  