Multiplication operator between raster and constant

[Jeongho-Han]

Hi @stevenpawley, I really appreciate this nice library.
I found multiplication between rasters works. but is there any way to multiply a raster (RasterLayer object) by a constant?
Because I got a raster predicted by the machine learning model that I trained, but I need to multiply that raster by a scale factor.

for example,
type(ras1): pyspatialml.rasterlayer.RasterLayer
ras2 = ras1 * 0.25