Some simplification [skip hazardlib][demos]
Some simplification [skip hazardlib][demos]


Former-commit-id: 736af2c5064aa1ecbeefeb63aeea42a4a6285aa7 [formerly 9e15282bd0dcb00fa20abef30945dc4df0d9c531]
Former-commit-id: 982e27741e59d5b1ad36e93c83abf804ab4a688b
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine