it seems better to validate against the init than against getDefaultPArameters (that one is almost empty)
this fixes a problem where the validation goes wrong if "Belos Solver" sublist is present in the newParams
This is wrong. The init params can only be set at initialization. This also holds for the Belos Solver parameters. Setting it afterward will do nothing, and therefore will throw an error.
it seems better to validate against the init than against getDefaultPArameters (that one is almost empty) this fixes a problem where the validation goes wrong if "Belos Solver" sublist is present in the newParams