Fit entrogram

[tlhenvironment]

I am wondering whether there is a simple way to fit an entrogram, to calculate range/sill values. Using gstat, it is possible to fit a variogram using two steps:

variogram() -> variogram_value
fit.variogram(variogram_value, vgm("Sph"))

Of course, I can't use the calculated entrogram with the fit.variogram() function, and manual transforming into a gstat-variogram object is quite annoying. Is there a better workflow for this? Probably I'm missing something.