clarify ability to take callable as indexer in docstring
@@ -95,9 +95,10 @@ class BIDSLayout(object):
in the root argument is reindexed. If False, indexing will be
skipped and the existing database file will be used. Ignored if
database_path is not provided.
- indexer: BIDSLayoutIndexer
- An optional BIDSLayoutIndexer to use for indexing. If None, a new
- indexer with default parameters will be created.
+ indexer: BIDSLayoutIndexer or callable
+ An optional BIDSLayoutIndexer instance to use for indexing, or any
+ callable that takes a BIDSLayout instance as its only argument. If
+ None, a new indexer with default parameters will be implicitly created.
indexer_kwargs: dict
Optional keyword arguments to pass onto the newly created
BIDSLayoutIndexer. Valid keywords are 'validate', 'ignore',
