def is_documentation_changes_only(files_string: str) -> bool:
    """

    Args:
        files_string: The modified files.

    Returns: True is only documentation related files has been changed else False.

    """
    # Check if only README file in file string, if so, no need to create the servers.
    files = [s for s in files_string.split('\n') if s]
    documentation_changes_only = \
        all(map(lambda s: s.endswith('.md') or s.endswith('.png') or s.endswith('.jpg') or s.endswith('.mp4'), files))
    if documentation_changes_only:
        return True
    else:
        return False