Assistant: 
User: 
    Please analyze the following code file and determine whether it belongs to any of the provided modules based on the listed module descriptions.
    Note that the provided list of modules may not be exhaustive, and some files may not belong to any of the modules. 
    If the code belongs to a module, Only output the module name, without any explanation or additional information; otherwise, return 'None' if it does not belong to any module.

    Modules : {
        "UI": "Handles the front-end user interface, consisting of HTML, CSS, and JavaScript files generated by the Angular framework. It processes user requests and interacts with the server using AJAX for data retrieval and client-side interactions."
"Test Driver": "Facilitates automated regression testing and handles transmission of test data in JSON format. It performs Java testing using TestNG and JavaScript unit-testing with Jest. It also sets up a simulated web server for servlet-level tests and automates end-to-end testing using Selenium Java."
"Logic": "Manages the business logic of TEAMMATES, including handling relationships between entities, managing transactions, input value sanitization, access control rights, and interfacing with GAE-provided or third-party APIs."
"Storage": "Performs CRUD operations on data entities, validation of data, and abstraction of GQL queries, hiding the complexities of datastore from the Logic component."
"Common": "Contains utility classes, custom exceptions, and data transfer objects used across the entire application for easy consolidation and transfer of structured data."
"E2E": "Handles end-to-end testing and load & performance testing, providing helpers, abstractions of browser pages, and test cases for E2E tests and L&P tests."
"Client": "Contains scripts for administrative tasks, such as migrating data to a new schema and calculating statistics. This module connects directly to the application back-end for administrative purposes."
    }

    Code: package teammates.logic.api; /** * Handles operations related to sending emails. */ public class EmailSender { private static final Logger log = Logger.getLogger(); private static final EmailSender instance = new EmailSender(); private final EmailSenderService service; EmailSender() { if (Config.IS_DEV_SERVER) { service = new EmptyEmailService(); } else { if (Config.isUsingSendgrid()) { service = new SendgridService(); } else if (Config.isUsingMailgun()) { service = new MailgunService(); } else if (Config.isUsingMailjet()) { service = new MailjetService(); } else { service = new EmptyEmailService(); } } } public static EmailSender inst() { return instance; } /** * Sends the given {@code message} and generates a log report. * * @return The HTTP status of the email request. */ public EmailSendingStatus sendEmail(EmailWrapper message) { if (isTestingAccount(message.getRecipient())) { return new EmailSendingStatus(HttpStatus.SC_OK, "Not sending email to test account"); } EmailSendingStatus status; EmailSendingException caughtE = null; try { status = service.sendEmail(message); } catch (EmailSendingException e) { caughtE = e; status = new EmailSendingStatus(e.getStatusCode(), e.getMessage()); } if (!status.isSuccess()) { if (caughtE == null) { log.severe("Email failed to send: " + status.getMessage()); } else { log.severe("Email failed to send: " + status.getMessage(), caughtE); } } EmailSentLogDetails details = new EmailSentLogDetails(); details.setEmailRecipient(message.getRecipient()); details.setEmailSubject(message.getSubject()); details.setEmailContent(message.getContent()); details.setEmailType(message.getType()); details.setEmailStatus(status.getStatusCode()); if (status.getMessage() != null) { details.setEmailStatusMessage(status.getMessage()); } log.event("Email sent: " + message.getType(), details); return status; } private boolean isTestingAccount(String email) { return email.endsWith(Const.TEST_EMAIL_DOMAIN); } }
    
Assistant: