Fixed node.to_str
Fixed node.to_str


Former-commit-id: c0e313c63675644f6740005f7d44f188dfe8fdb2 [formerly caf5620a6bd1706f6c0aa4c1d95d823670b2edc4]
Former-commit-id: 90e31a0713e410e1a11d00995317251026fac617
gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine,gem/oq-engine