I was wondering whether there is a neat way of converting a split ODE problem of the form `SplitODEProblem{isinplace}(f1,f2,u0,tspan,p=NullParameters();kwargs...)`

to an usual ODE problem

`ODEProblem{isinplace,specialize}(f,u0,tspan,p=NullParameters();kwargs...)`

.

Mathematically, this corresponds to f_1 + f_2 = f; in code, however, I cannot simply add the functions f_1, f_2 and am thus interested in this functionality.