docs: def load(self, list_file):
      """Loads the list of annotations from the given file and **appends** it to the current list.
  
      ``list_file`` : str
        The name of a list file to load and append
      """
      with open(list_file) as f:
        for line in f:
          if line and line[0] != '#':
            splits = line.split()
            bounding_boxes = []
            for i in range(1, len(splits), 4):
              assert splits[i][0] == '[' and splits[i+3][-1] == ']'
              bounding_boxes.append(BoundingBox(topleft=(float(splits[i][1:]), float(splits[i+1])), size=(float(splits[i+2]), float(splits[i+3][:-1]))))
            self.image_paths.append(splits[0])
            self.bounding_boxes.append(bounding_boxes)