def rm_lb_hyphens(plain_root, logger, ignore=['.json', '.log', '.err']):
    """
    Looks for a hyphen followed by whitespace or a line break.

    Reconstructs word and checks to see if the result exists in either
    WordNet or the OS's default spellchecker dictionary. If so,
    replaces fragments with reconstructed word.
    
    :param plain_root: The name of the directory containing plain-text 
        files.
    :type plain_root: string
    
    :param logger: Logger that handles logging for the given directory.
    :type logger: Logger
    
    :param ignore: List of file extensions to ignore in the directory.
    :type ignore: list of strings, optional

    :returns: None
    """
    pass
