If a chef node has an attribute set on multiple levels to dictionary values, then the dictionary produced by NodeAttributes.to_dict() only contains the items in the dictionary set at the level with higher precedence, omitting the items that only exist in the dictionary set at the level with lower precedence. For example, if "postgresql" is set on the default level to {"version": "9.5"} and on the normal level to {"enable_pgdg_apt": true}, then the "postgresql" key in the output of to_dict() would have the value of {"enable_pgdg_apt": True} instead of {"enable_pgdg_apt": True, "version": "9.5"}.