R语言 Error:xdatis not a NpdeData object.报错

问题阐释：

Error:xdatis not a NpdeData object.

Function npdeSimData requires two mandatory arguments: first, a NpdeData object created by a call to npdeData() (see help page for the syntax of that function), and the name of a matching dataset containing the simulated data (either a file on disk or a data.frame. Please refer to the documentation for details and examples.

Error in (function (cl, name, valueClass) :
assignment of an object of class “character” is not valid for @‘data’ in an object of class “NpdeObject”; is(value, "NpdeData") is not TRUE.