def load_directory(self, top_path, followlinks):
        """
        Traverse top_path directory and save patterns in any .ddsignore files found.
        :param top_path: str: directory name we should traverse looking for ignore files
        :param followlinks: boolean: should we traverse symbolic links
        """
        for dir_name, child_dirs, child_files in os.walk(top_path, followlinks=followlinks):
            for child_filename in child_files:
                if child_filename == DDS_IGNORE_FILENAME:
                    pattern_lines = self._read_non_empty_lines(dir_name, child_filename)
                    self.add_patterns(dir_name, pattern_lines)
Traverse top_path directory and save patterns in any .ddsignore files found.
        :param top_path: str: directory name we should traverse looking for ignore files
        :param followlinks: boolean: should we traverse symbolic links