code: def initialize_new_session():
      
      if 'image_uid_counter' in session and 'image_list' in session:
          logger.debug('images are already being tracked')
      else:
          # reset image list counter for the session
          session['image_uid_counter'] = 0
          session['image_list'] = []
      if 'img_input_dir' in session and 'img_output_dir' in session:
          logger.debug('temporary image directories already exist')
      else:
          # make image upload directory
          session['img_input_dir'] = mkdtemp()
          session['img_output_dir'] = mkdtemp()
docs: Check session and initialize if necessary
  
      Before every request, check the user session.  If no session exists, add
      one and provide temporary locations for images