code: def display_candidates(self, tree, html_path, filename_prefix):
          
          imgs = self.display_boxes(
              tree, html_path, filename_prefix, alternate_colors=True
          )
          return display(*imgs)
docs: Displays the bounding boxes corresponding to candidates on an image of the pdf
          boxes is a list of 5-tuples (page, top, left, bottom, right)