def key_columns(self):
        return ", ".join([quote_id(col) for col in self.col_names])
If no authors are found in the changeset, default to a fake
dataset/ETHPy150Open perseas/Pyrseas/pyrseas/dbobject/constraint.py/Constraint.key_columns--crossover with--dataset/ETHPy150Open mozilla/pontoon/pontoon/sync/tests/test_core.py/CommitChangesTests.test_no_authors