docs: def defaults(f, self, *args, **kwargs):
      """
      For ``PARAMETERS`` keys, replace None ``kwargs`` with ``self`` attr values.
  
      Should be applied on the top of any decorator stack so other decorators see
      the "right" kwargs.
  
      Will also apply transformations found in ``TRANSFORMS``.
      """
      for name, data in PARAMETERS.iteritems():
          kwargs[name] = kwargs.get(name) or getattr(self, name)
          if 'transform' in data:
              kwargs[name] = data['transform'](kwargs[name])
      return f(self, *args, **kwargs)