input: Write a function to compute the average of every two numbers in a list.
  assert average_every_two_numbers([1, 3, 5, 7, 9]) == [2.0, 6.0, 9]
  assert average_every_two_numbers([2, 4, 6, 8, 10, 12]) == [3.0, 7.0, 11.0]
  assert average_every_two_numbers([5, 10, 15, 20, 25]) == [7.5, 17.5, 25]
output: def average_every_two_numbers(lst):
      result = []
      for i in range(0, len(lst), 2):
          if i + 1 < len(lst):
              result.append((lst[i] + lst[i + 1]) / 2)
          else:
              result.append(lst[i])
      return result