+ def apply(self, proposed_contents: Any, ignored_filename: str = None) -> bool:
+ """Call this before writing a new file to directory with the
+ proposed_contents to be written and it will return a value that
+ indicates whether the identical contents is already sitting in
+ *any* file in that directory. Useful, e.g., for caching.
+
+ Args:
+ proposed_contents: the contents about to be persisted to
+ directory
+ ignored_filename: unused for now, must be None
+
+ Returns:
+ True if proposed contents does not yet exist in any file in
+ directory or False if it does exist in some file already.
+ """