Boundary conditions at infinity with dsolve

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(I have a feeling this will be trivial, but maybe others have come across this too)

So I'm just testing desolve with this equation:

de = a*diff(x*f) + .5*sigma*diff(f,x,2)

and if I specify the initial conditions in desolve like this

h = desolve(de, f, ics = [-Infinity, 0., Infinity, 0.])

... and I get h=0. Huh?? I couldn't find practically anything on how Sage handles BC at infinities...