def split_emails(msg):
    """
    Given a message (which may consist of an email conversation thread with
    multiple emails), mark the lines to identify split lines, content lines and
    empty lines.

    Correct the split line markers inside header blocks. Header blocks are
    identified by the regular expression RE_HEADER.

    Return the corrected markers
    """
    msg_body = _replace_link_brackets(msg)

    # don't process too long messages
    lines = msg_body.splitlines()[:MAX_LINES_COUNT]
    markers = remove_initial_spaces_and_mark_message_lines(lines)

    markers = _mark_quoted_email_splitlines(markers, lines)

    # we don't want splitlines in header blocks
    markers = _correct_splitlines_in_headers(markers, lines)

    return markers
Given a message (which may consist of an email conversation thread with
    multiple emails), mark the lines to identify split lines, content lines and
    empty lines.

    Correct the split line markers inside header blocks. Header blocks are
    identified by the regular expression RE_HEADER.

    Return the corrected markers