 
                            Several well-known adages in object-oriented design suggest that the dependency structure of a package or module must never contain cycles; that is, it must be representable as a directed acyclic graph (DAG).
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                            Several well-known adages in object-oriented design suggest that the dependency structure of a package or module must never contain cycles; that is, it must be representable as a directed acyclic graph (DAG).
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