def __init__(self, *, metadata: dict[str, Any] | None = None, solve_config: dict[str, Any] | None = None) -> None:
self.graph = Graph()
self.metadata = dict(metadata or {})
self.solve_config = dict(solve_config or {})
self.variable_ids: list[int] = []
self.objective_ids: list[int] = []
self.constraint_ids: list[int] = []
self.external_specs: dict[str, dict[str, Any]] = {}