def METHOD_NAME(msg):
    """
    Processes a Git commit message to ensure it meets the Git commit style guidelines documented at:
        https://github.com/linkedin/Brooklin/blob/master/CONTRIBUTING.md#git-commit-messages-style-guide
    Args:
        msg (str):  The entire Git commit message (possibly multiline)
    Returns:
        str: The processed message with minor improvements applied if applicable.
             These improvements are:
                - Capitalizing first letter of subject line
                - Removing periods from the end of subject line
                - Inserting a newline between subject line and description
                - Wrapping the description at 100 characters
    Raises:
        ValueError: if msg contains style violations that cannot be fixed automatically
                    These violations are:
                        1. A subject line whose length exceeds 120 characters
                        2. A reference to an internal Jira ticket (DDSDBUS, LISAMZA, or DATAPIPES)
    """
    if not msg:
        return msg
    # Filter out comments as well as empty lines added by previous Git hooks
    msg_lines = []
    for msg_line in msg.splitlines():
        msg_line = msg_line.strip()
        if msg_line and not msg_line.startswith('#'):
            msg_lines.append(msg_line)
    # If msg is composed entirely of new lines or comments, just return it as is.
    if not msg_lines:
        return msg
    subject = msg_lines[0].strip()
    # Limit the subject line to 120 characters
    if len(subject) > MAX_SUBJECT_LENGTH:
        raise ValueError("Commit message subject line is too long [{} chars max]".format(MAX_SUBJECT_LENGTH))
    # Do not make references to internal Jira tickets
    if re.search('(DDSDBUS|LISAMZA|DATAPIPES)-\d+', "".join(msg_lines), flags=re.IGNORECASE):
        raise ValueError("Commit messages must not reference internal Jira tickets (DDSDBUS, LISAMZA, DATAPIPES)")
    # Capitalize the subject line
    if subject[0].islower():
        subject = subject.capitalize()
        print_warning("Capitalized first letter of commit message subject line")
    # Do not end the subject line with a period
    if subject[-1] == '.':
        subject = subject.rstrip(".")
        if not subject:
            raise ValueError("Commit messages cannot have subject lines composed entirely of periods")
        print_warning("Removed trailing period(s) from commit message subject line")
    # Wrap the body at 100 characters
    description = []
    for desc_line in msg_lines[1:]:
        description.append("\n".join(textwrap.wrap(desc_line, MAX_DESCRIPTION_LINE_LENGTH)))
    if any(len(line) > MAX_DESCRIPTION_LINE_LENGTH for line in msg_lines):
        print_warning("Wrapping lines longer than {} chars in commit message description".format(MAX_DESCRIPTION_LINE_LENGTH))
    # Separate subject from body with a blank line
    return subject if not description else subject + "\n\n" + "\n".join(description)