Return tab title.

def get_tab_text(self, index, is_modified=None, is_readonly=None):
        """Return tab title."""
        files_path_list = [finfo.filename for finfo in self.data]
        fname = self.data[index].filename
        fname = sourcecode.disambiguate_fname(files_path_list, fname)
        return self.__modified_readonly_title(fname,
                                              is_modified, is_readonly)