`gradient_cloud` throws error regardless of arguments

[llyrjones9]

gradient_cloud seems to be broken.

I have tried the following example from the reference manual, along with some of my own examples. The same error is produced regardless.

The bug originates at the bottom of the gradient_cloud.R file in the drop.levels function, where a required argument is not supplied.

I am using qdap 2.4.3 on RStudio 4.0.4

This example worked fine with qdap 2.3.6 on RStudio 3.6.3