public function send_mail_list() {
		$error = new WP_Error();

		if ( empty( $_GET['event_id'] ) ) {
			$error->add( 'no-event-id', esc_html__( 'Invalid Event ID', 'event-tickets' ), array( 'type' => 'general' ) );

			return $error;
		}

		$cap      = 'edit_posts';
		$event_id = absint( ! empty( $_GET['event_id'] ) && is_numeric( $_GET['event_id'] ) ? $_GET['event_id'] : 0 );

		if ( ! current_user_can( 'edit_posts' ) && $event_id ) {
			$event = get_post( $event_id );

			if ( $event instanceof WP_Post && get_current_user_id() === (int) $event->post_author ) {
				$cap = 'read';
			}
		}

		if ( empty( $_POST['_wpnonce'] ) || ! wp_verify_nonce( $_POST['_wpnonce'], 'email-attendees-list' ) || ! $this->user_can( $cap, $_GET['event_id'] ) ) {
			$error->add( 'nonce-fail', esc_html__( 'Cheatin Huh?', 'event-tickets' ), array( 'type' => 'general' ) );

			return $error;
		}

		if ( empty( $_POST['email_to_address'] ) && ( empty( $_POST['email_to_user'] ) || 0 >= (int) $_POST['email_to_user'] ) ) {
			$error->add( 'empty-fields', esc_html__( 'Empty user and email', 'event-tickets' ), array( 'type' => 'general' ) );

			return $error;
		}

		if ( ! empty( $_POST['email_to_address'] ) ) {
			$type = 'email';
		} else {
			$type = 'user';
		}

		if ( 'email' === $type && ! is_email( $_POST['email_to_address'] ) ) {
			$error->add( 'invalid-email', esc_html__( 'Invalid Email', 'event-tickets' ), array( 'type' => $type ) );

			return $error;
		}

		if ( 'user' === $type && ! is_numeric( $_POST['email_to_user'] ) ) {
			$error->add( 'invalid-user', esc_html__( 'Invalid User ID', 'event-tickets' ), array( 'type' => $type ) );

			return $error;
		}

		/**
		 * Now we know we have valid data
		 */

		if ( 'email' === $type ) {
			// We already check this variable so, no harm here
			$email = $_POST['email_to_address'];
		} else {
			$user = get_user_by( 'id', $_POST['email_to_user'] );

			if ( ! is_object( $user ) ) {
				$error->add( 'invalid-user', esc_html__( 'Invalid User ID', 'event-tickets' ), array( 'type' => $type ) );

				return $error;
			}

			$email = $user->data->user_email;
		}

		$this->attendees_table = new Tribe__Tickets__Attendees_Table();
		$items = $this->generate_filtered_list( $_GET['event_id'] );

		$event = get_post( $_GET['event_id'] );

		ob_start();
		$attendee_tpl = Tribe__Tickets__Templates::get_template_hierarchy( 'tickets/attendees-email.php', array( 'disable_view_check' => true ) );
		include $attendee_tpl;
		$content = ob_get_clean();

		add_filter( 'wp_mail_content_type', array( $this, 'set_contenttype' ) );

		if ( ! wp_mail( $email, sprintf( esc_html__( 'Attendee List for: %s', 'event-tickets' ), $event->post_title ), $content ) ) {
			$error->add( 'email-error', esc_html__( 'Error when sending the email', 'event-tickets' ), array( 'type' => 'general' ) );

			return $error;
		}

		remove_filter( 'wp_mail_content_type', array( $this, 'set_contenttype' ) );

		return esc_html__( 'Email sent successfully!', 'event-tickets' );
	}