Factory for creating owners, based on --sort option.

def build_owner(args):
    """Factory for creating owners, based on --sort option."""
    if args.sort_by == 'cover':
        return CoverageOwners(args.root, args.verbose)
    if os.path.isdir(args.root):
        pass
    else:  # File
        args.root, args.filter = os.path.split(args.root)
    if args.sort_by == 'date':
        return DateOwners(args.root, args.filter, args.details,
                          args.verbose, args.max)
    else:  # by size
        return SizeOwners(args.root, args.filter, args.details,
                          args.verbose, args.max)