| AcceptedElems | Elements that can be passed to manipulation methods, including functions. |
| AcceptedFilters | Supported filter types, for traversal methods. |
| BasicAcceptedElems | Elements that can be passed to manipulation methods. |
| FilterFunction | Function signature, for traversal methods. |
| SelectorType | Type for identifying selectors. Allows us to "upgrade" queries using
selectors to return |