def _split(self, index):
if index is None:<EOL><INDENT>return None<EOL><DEDENT>split = index.split('<STR_LIT:.>')<EOL>if split == ['<STR_LIT>']:<EOL><INDENT>return []<EOL><DEDENT>return split<EOL>
Splits :index: by '.', removing empty strings.

        If None is supplied, None is returned.

        :index: Index to split.
        :returns: :index: split by '.' or empty list, if there are no items.