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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:

def send(self, test=None):
        '''
        Send the email through the Postmark system.
        Pass test=True to just print out the resulting
        JSON message being sent to Postmark
        '''
        self._check_values()

        # Set up message dictionary
        json_message = self.to_json_message()

        # if (self.__html_body and not self.__text_body) and self.__multipart:
        #     # TODO: Set up regex to strip html
        #     pass

        # If test is not specified, attempt to read the Django setting
        if test is None:
            try:
                from django.conf import settings as django_settings
                test = getattr(django_settings, "POSTMARK_TEST_MODE", None)
            except ImportError:
                pass

        # If this is a test, just print the message
        if test:
            print('JSON message is:\n%s' % json.dumps(json_message, cls=PMJSONEncoder))
            return

        if self.__template_id:
            endpoint_url = __POSTMARK_URL__ + 'email/withTemplate/'
        else:
            endpoint_url = __POSTMARK_URL__ + 'email'

        # Set up the url Request
        req = Request(
            endpoint_url,
            json.dumps(json_message, cls=PMJSONEncoder).encode('utf8'),
            {
                'Accept': 'application/json',
                'Content-Type': 'application/json',
                'X-Postmark-Server-Token': self.__api_key,
                'User-agent': self.__user_agent
            }
        )

        # Attempt send
        try:
            # print 'sending request to postmark: %s' % json_message
            result = urlopen(req)
            jsontxt = result.read().decode('utf8')
            result.close()
            if result.code == 200:
                self.message_id = json.loads(jsontxt).get('MessageID', None)
                return True
            else:
                raise PMMailSendException('Return code %d: %s' % (result.code, result.msg))
        except HTTPError as err:
            if err.code == 401:
                raise PMMailUnauthorizedException('Sending Unauthorized - incorrect API key.', err)
            elif err.code == 422:
                try:
                    jsontxt = err.read().decode('utf8')
                    jsonobj = json.loads(jsontxt)
                    desc = jsonobj['Message']
                    error_code = jsonobj['ErrorCode']
                except KeyError:
                    raise PMMailUnprocessableEntityException('Unprocessable Entity: Description not given')

                if error_code == 406:
                    raise PMMailInactiveRecipientException('You tried to send email to a recipient that has been marked as inactive.')

                raise PMMailUnprocessableEntityException('Unprocessable Entity: %s' % desc)
            elif err.code == 500:
                raise PMMailServerErrorException('Internal server error at Postmark. Admins have been alerted.', err)
        except URLError as err:
            if hasattr(err, 'reason'):
                raise PMMailURLException('URLError: Failed to reach the server: %s (See "inner_exception" for details)' % err.reason, err)
            elif hasattr(err, 'code'):
                raise PMMailURLException('URLError: %d: The server couldn\'t fufill the request. (See "inner_exception" for details)' % err.code, err)
            else:
                raise PMMailURLException('URLError: The server couldn\'t fufill the request. (See "inner_exception" for details)', err)