Algorithm type for the solver; can be `dpmsolver` or `dpmsolver++` or `sde-dpmsolver++`. The `dpmsolver`
type implements the algorithms in the [DPMSolver](https://huggingface.co/papers/2206.00927) paper, and the
`dpmsolver++` type implements the algorithms in the [DPMSolver++](https://huggingface.co/papers/2211.01095)
paper. It is recommended to use `dpmsolver++` or `sde-dpmsolver++` with `solver_order=2` for guided
sampling like in Stable Diffusion.
solver_type (`str`, defaults to `midpoint`):