Add defaults to docstring
@@ -671,10 +671,11 @@ class MetadataSourcePlugin(object):
:param artists: Iterable of artist dicts or lists returned by API.
:type artists: list[dict] or list[list]
:param id_key: Key or index corresponding to the value of ``id`` for
- the main/first artist.
+ the main/first artist. Defaults to 'id'.
:type id_key: str or int
:param name_key: Key or index corresponding to values of names
to concatenate for the artist string (containing all artists).
+ Defaults to 'name'.
:type name_key: str or int
:return: Normalized artist string.
:rtype: str
