Restored parallel.Sequential
Restored parallel.Sequential


Former-commit-id: 4b725dad14afdfc731f760043ec8265b9ff8c4c0 [formerly 5e1c3817e74596452eb45b60b5b78ce420161d99]
Former-commit-id: ab28f745bbf16440c2bfe1ee73ef8ebacbc734da
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine