What steps will reproduce the problem? 1. Create a metric at the domain level (general) and do not create any metric specific to the problem instance 2. Translate the domain to pddl 3. Translate the problem to pddl

What is the expected output? What do you see instead? The translation of the problem instance is blank. The problems occurs only at this situattion. It is giving an expection when reading the domain metrics when the specific metrics are completly empty.

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fixed for the next release (e.g. 4.0)