DAG in _condition_tree.py missing __eq__() method

Hi, I am trying to compare equivalent configuration objects, but they are being considered not equal due to missing __eq__() method in the DAG class in _condition_tree.py.

Start by reading the DAG class in _condition_tree.py and reproduce the reported comparison of equivalent configuration objects. Define the equality behavior from the existing class structure, implement the missing method, and run the relevant test suite to verify that equivalent objects compare equal without breaking existing behavior.

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