code: def one(cls, path='', index=0):
          
          url = urljoin(cls._meta.base_url, path)
          pq_items = cls._get_items(url=url, **cls._meta._pyquery_kwargs)
          item = pq_items.eq(index)
          if not item:
              raise ItemDoesNotExist("%s not found" % cls.__name__)
          return cls(item=item)
docs: Return ocurrence (the first one, unless specified) of the item.