The has_files() and has_files_re() methods could be replaced with find() and find_re(). They add a considerable amount of bloat and should thus be removed.
The SpecFile.find() method works as DataSource.find_re(). It should be renamed to SpecFile.find_re() to make things consistent
fixed in c82ad12bbae5ae1 and 42cdd720f17464b039