def warn(self, msg, whitespace_strp=True):
        """
        For things that have gone seriously wrong but don't merit a program
        halt.
        Outputs to stderr, so JsonOutput does not need to override.
        @param msg: warning to output.
        @param whitespace_strp: whether to strip whitespace.
        """
        if self.errors_display:
            if whitespace_strp:
                msg = strip_whitespace(msg)

            if not self.log_to_file:
                msg = colors['warn'] + "[+] " + msg + colors['endc']
            else:
                msg = "[" + time.strftime("%c") + "] " + msg

            self.print(msg, file=self.error_log)