code: def breadcrumb(self):
          
          ret = []
          here = self
          while here:
              ret.append(here)
              here = here.parent
          return list(reversed(ret))
docs: Get the category hierarchy leading up to this category, including
          root and self.
  
          For example, path/to/long/category will return a list containing
          Category('path'), Category('path/to'), and Category('path/to/long').