do not use directly

def send_error_explain(self, code, message=None, headers=None, content_type=None):
        "do not use directly"
        if headers is None:
            headers = {}

        if code in self.responses:
            if message is None:
                message = self.responses[code][0]

            explain = self.responses[code][1]
        else:
            explain = ""

        if message is None:
            message = ""

        if not isinstance(headers, dict):
            headers = {}

        if not content_type:
            if self._cmd and self._cmd.content_type:
                content_type = self._cmd.content_type
            else:
                content_type = self._DEFAULT_CONTENT_TYPE

        if self._cmd and self._cmd.charset:
            charset = self._cmd.charset
        else:
            charset = DEFAULT_CHARSET

        headers['Content-type'] = "%s; charset=%s" % (content_type, charset)

        data = self._mk_error_explain_data(code, message, explain)

        self.end_response(self.build_response(code, data, headers))