How to use the catalogue.models.Record function in catalogue

def setUp(self):
        # Generate a test user for endpoint responses.
        self.testuser = User.objects.create_user(
            username='testuser', email='user@dbca.wa.gov.au.com', password='pass')
        # Log in testuser by default.
        self.client.login(username='testuser', password='pass')
        # Generate some Record objects.
        mixer.cycle(8).blend(Record, title=mixer.RANDOM)

def test_list_filter(self):
        url = '/catalogue/api/records/'
        params = {'format': 'json'}
        resp = self.client.get(url, data=params)
        unfiltered = json.loads(resp.content.decode('utf-8'))
        records = Record.objects.all()
        rec1, rec2 = records[0], records[1]
        # Generate an Application
        app = mixer.blend(Application, name='test')
        app.records.add(rec1)
        params = {'format': 'json', 'application__name': 'test'}
        resp = self.client.get(url, data=params)
        self.assertEqual(resp.status_code, 200)
        self.assertContains(resp, rec1.title)
        self.assertNotContains(resp, rec2.title)
        # The filtered response will be shorter than the unfiltered one.
        filtered = json.loads(resp.content.decode('utf-8'))
        self.assertTrue(len(unfiltered) > len(filtered))

class StyleInline(admin.StackedInline):
    model = models.Style
    extra = 1
    
@admin.register(models.Style)
class StyleAdmin(admin.ModelAdmin):
    list_display = ('name','record','format',)
    
    def get_readonly_fields(self, request, obj=None):
        if obj:
            return self.readonly_fields + ('name',)
        return self.readonly_fields
    
    
@admin.register(models.Record)
class RecordAdmin(admin.ModelAdmin):
    list_display = ("id", "identifier", "title",)
    inlines = [StyleInline,]
    readonly_fields = ('publication_date','modified',)
    
    def get_readonly_fields(self, request, obj=None):
        if obj:
            return self.readonly_fields + ('identifier',)
        return self.readonly_fields


@admin.register(models.Organization)
class OrganizationAdmin(admin.ModelAdmin):
    inlines = [CollaboratorInline,]

    @property
    def qml(self):
        """
        The default sld style file
        if not exist, return None
        """
        return self.default_style("QML")
    
class Style(models.Model):
    FORMAT_CHOICES = (
        ('SLD','SLD'),
        ('QML','QML'),
        ('LYR','LAYER')
    )
    record = models.ForeignKey(Record, related_name='styles',null=True)
    name = models.CharField(max_length=255)
    format = models.CharField(max_length=3, choices=FORMAT_CHOICES)
    default = models.BooleanField(default=False)
    content = models.FileField(upload_to='{0}/catalogue/styles'.format(settings.MEDIA_ROOT),blank=True, default='')
    checksum = models.CharField(blank=True,max_length=255, editable=False)
    def clean(self):
        from django.core.exceptions import ValidationError
        try:
            duplicate = Style.objects.exclude(pk=self.pk).get(record=self.record,format=self.format,default=True)
            if duplicate and self.default:
                raise ValidationError('There can only be one default format style for each record')
        except Style.DoesNotExist:
            pass
    
    def save(self, *args, **kwargs):
        update_fields=None