weights is a generic function which extracts fitting weights from
objects returned by modeling functions.
Methods can make use of napredict methods to compensate
for the omission of missing values. The default methods does so.
weights(object, …)an object for which the extraction of model weights is meaningful.
other arguments passed to methods.
Weights extracted from the object object: the default method
looks for component "weights" and if not NULL calls
napredict on it.
Chambers, J. M. and Hastie, T. J. (1992) Statistical Models in S. Wadsworth & Brooks/Cole.