How to use the unidiff.constants.RE_HUNK_HEADER.match function in unidiff

def _parse_hunk(self, header, diff, encoding):
        """Parse hunk details."""
        header_info = RE_HUNK_HEADER.match(header)
        hunk_info = header_info.groups()
        hunk = Hunk(*hunk_info)

        source_line_no = hunk.source_start
        target_line_no = hunk.target_start
        expected_source_end = source_line_no + hunk.source_length
        expected_target_end = target_line_no + hunk.target_length

        for diff_line_no, line in diff:
            if encoding is not None:
                line = line.decode(encoding)

            valid_line = RE_HUNK_BODY_LINE.match(line)
            if not valid_line:
                valid_line = RE_HUNK_EMPTY_BODY_LINE.match(line)

if is_target_filename:
                if current_file is not None and not current_file.is_rename:
                    raise UnidiffParseError('Target without source: %s' % line)
                target_file = is_target_filename.group('filename')
                target_timestamp = is_target_filename.group('timestamp')
                if current_file is None:
                    # add current file to PatchSet
                    current_file = PatchedFile(
                        patch_info, source_file, target_file,
                        source_timestamp, target_timestamp)
                    self.append(current_file)
                    patch_info = None
                continue

            # check for hunk header
            is_hunk_header = RE_HUNK_HEADER.match(line)
            if is_hunk_header:
                if current_file is None:
                    raise UnidiffParseError('Unexpected hunk found: %s' % line)
                current_file._parse_hunk(line, diff, encoding)
                continue

            # check for no newline marker
            is_no_newline = RE_NO_NEWLINE_MARKER.match(line)
            if is_no_newline:
                if current_file is None:
                    raise UnidiffParseError('Unexpected marker: %s' % line)
                current_file._add_no_newline_marker_to_last_hunk()
                continue

            # sometimes hunks can be followed by empty lines
            if line == '\n' and current_file is not None:

source_timestamp = check_source.group('timestamp')
            current_patch = None
            continue

        # check for target file header
        check_target = RE_TARGET_FILENAME.match(line)
        if check_target:
            target_file = check_target.group('filename')
            target_timestamp = check_target.group('timestamp')
            current_patch = PatchedFile(source_file, target_file,
                                        source_timestamp, target_timestamp)
            ret.append(current_patch)
            continue

        # check for hunk header
        re_hunk_header = RE_HUNK_HEADER.match(line)
        if re_hunk_header:
            hunk_info = re_hunk_header.groups()
            hunk = _parse_hunk(diff, *hunk_info)
            current_patch.append(hunk)
    return ret