I need to work with individual Wiener increments from an SDE solution in my loss function. Whenever I try to get these values from `sol.W.W`

command, the `ERROR: type Nothing has no field W`

pops up when computing the gradients. Can it be a bug in DiffEqSensitivity package?

MWE:

```
using DifferentialEquations, Flux, DiffEqFlux
using DiffEqSensitivity
function dt!(du, u, p, t)
x, y = u
α, β, δ, γ = p
du[1] = dx = α*x - β*x*y
du[2] = dy = -δ*y + γ*x*y
end
function dW!(du, u, p, t)
du[1] = 0.1u[1]
du[2] = 0.1u[2]
end
u0 = [1.0,1.0]
tspan = (0.0, 10.0)
p = [2.2, 1.0, 2.0, 0.4]
W = WienerProcess(0.0,0.0,0.0)
prob_sde = SDEProblem(dt!, dW!, u0, tspan,p,noise=W)
function some_loss(p) #some loss function
sol=solve(prob_sde, EM(), saveat = 0.1,sensealg = ForwardDiffSensitivity(), dt=0.001)
Wsum=sum(sol.W.W) #problematic part
println("Wsum=",Wsum)
sum(abs2, x-1 for x in Array(sol))
end
ps = Flux.params(p)
@time gs = gradient(ps) do
some_loss(p)
end #ERROR: type Nothing has no field W
```