Added a docstring
Added a docstring


Former-commit-id: 227e5a902858416a56e05a50a5f50d0c06b89db9 [formerly 9d4eebac44e6934b0fc864ad25f527a4a0ff4252]
Former-commit-id: 4f8efa4a00d19f4e8e0356ba5f31e5377d83d0c8
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine