corrected doc string
corrected doc string


Former-commit-id: 9f03d0df84812dba58443ee0bb6ff565781b5afc [formerly 502c20972733ef4da66dc427d8787ec6ee39c4ed]
Former-commit-id: ea616aabbfd5a52379d9adc9f68bf3cbd9ac72c2
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine