code: def versioned_url(self):
          '''A property returning the url of the recipe with ``{version}``
          replaced by the :attr:`url`. If accessing the url, you should use this
          property, *not* access the url directly.'''
          if self.url is None:
              return None
          return self.url.format(version=self.versionf versioned_url(self):
          '''A property returning the url of the recipe with ``{version}``
          replaced by the :attr:`url`. If accessing the url, you should use this
          property, *not* access the url directly.'''
          if self.url is None:
              return None
          return self.url.format(version=self.version)
docs: A property returning the url of the recipe with ``{version}``
          replaced by the :attr:`url`. If accessing the url, you should use this
          property, *not* access the url directly.