@classmethod<EOL><INDENT>def to_barrier_key(cls, barrier_index_key):<DEDENT>
barrier_index_path = barrier_index_key.to_path()<EOL>(pipeline_kind, dependent_pipeline_id,<EOL>unused_kind, purpose) = barrier_index_path[-<NUM_LIT:4>:]<EOL>barrier_record_path = (<EOL>pipeline_kind, dependent_pipeline_id,<EOL>_BarrierRecord.kind(), purpose)<EOL>return db.Key.from_path(*barrier_record_path)<EOL>
Converts a _BarrierIndex key to a _BarrierRecord key.

        Args:
          barrier_index_key: db.Key for a _BarrierIndex entity.

        Returns:
          db.Key for the corresponding _BarrierRecord entity.