Revert "merge changes with upstream since"

This reverts commit eb3036b08f2a98a1d72a81a81802f069bce635a2.
Revert "Merge branch 'develop' of https://github.com/ghisvail/pykrylov into develop"

This reverts commit d0f4bfb28f04ea2a5029340983c72d402deeae4f, reversing
changes made to eb3b9a198248c7d7535ecc7698777512e061f55d.