Find duplicates in xs based on some criteria.
Find duplicates in xs based on some criteria.
type of
where to look for duplicates
the criteria used to determine duplicates.
Get the default namespace index mapping and the mapping from each namespace name to the feature index.
Get the default namespace index mapping and the mapping from each namespace name to the feature index.
If an error occurred, provide the error message; otherwise, return None for no error.
If an error occurred, provide the error message; otherwise, return None for no error.