added docstrings
added docstrings


Former-commit-id: 06436e66b651b582c8d56f5c821af68a7c664794 [formerly 37e7ad85f0622a3b6062124b63c3df0e340dda07]
Former-commit-id: 63fe7d5365fa498df1e463a6c638cab64f8648ec
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine