def search(self, included_nodes: Set[UniqueId], selector: str) -> Iterator[UniqueId]:
        """yields model nodes matching the specified access level"""
        for unique_id, node in self.parsed_nodes(included_nodes):
            if not isinstance(node, ModelNode):
                continue
            if selector == node.access:
                yield unique_id
yields model nodes matching the specified access level
core/dbt/graph/selector_methods.py