public ZonedDateTime getLastSignInOrActivatedAtOrCreatedAt() {
        if (this.getLastSignInAt() != null) {
            return this.getLastSignInAt();
        }
        else if (this.getActivatedAt() != null) {
            return this.getActivatedAt();
        }

        return this.getCreatedAt();
    }
@Test
    void testGetLastSignInOrActivatedAtOrCreatedAt() {
        var currentDate = ZonedDateTime.now();

        var appAuthenticator = new AppAuthenticator();
        appAuthenticator.setCreatedAt(currentDate);

        assertEquals(currentDate, appAuthenticator.getLastSignInOrActivatedAtOrCreatedAt());
    }