input: def rearrange_every_third_element(l: list):
      """This function takes a list l and returns a new list where elements with indices divisible by three
      are sorted, while the other elements remain in their original positions.
      >>> rearrange_every_third_element([1, 2, 3])
      [1, 2, 3]
      >>> rearrange_every_third_element([5, 6, 3, 4, 8, 9, 2])
      [2, 6, 3, 4, 8, 9, 5]
      """
output:     
      third_elements = l[::3]
      third_elements.sort()
      
      result = l[:]
      j = 0
      
      for i in range(len(l)):
          if i % 3 == 0:
              result[i] = third_elements[j]
              j += 1
              
      return result
  