How should I get derivatives from scipy RBFInterpolator? (simply, as with bisplev)

Question about scipy.interpolate.RBFInterpolator

I've found RBF gives much smoother 2D interpolation results than B-Splines via scipy.interpolate.bisplref with my particular data, but I need to take derivatives of what I get. When I evaluate the B-Splines using scipy.interpolate.bisplev, I can specify dx and dy to get any order of derivative in each dimention. Is there a similar sort of thing for RBFInterpolator that I'm just not seeing in the documentation? Or should I just take the gradient of the evaluated spline w/ numpy.gradient?

from How should I get derivatives from scipy RBFInterpolator? (simply, as with bisplev)