Returns the na.action component recorded during the build step.
# S3 method for pw_fit
na.action(object, ...)The na.action object recorded by est_pw during
the build step: an integer vector of the nonprobability-sample rows omitted
because of missing participation model variables (of class "omit" or
"exclude"), or NULL if no rows were omitted.
An object of class "pw_fit" returned by est_pw.
Additional arguments (not used).