diff --git a/.github/workflows/pylint.yml b/.github/workflows/pylint.yml
index 26a95c0..75d6199 100644
--- a/.github/workflows/pylint.yml
+++ b/.github/workflows/pylint.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        python-version: ["3.9", "3.10"]
+        python-version: ["3.10", "3.11", "3.12"]
     steps:
     - uses: actions/checkout@v3
     - name: Set up Python ${{ matrix.python-version }}
@@ -22,4 +22,4 @@ jobs:
         python setup.py install
     - name: Analysing the code with pylint
       run: |
-        pylint --rcfile=.pylintrc $(git ls-files '*.py')
\ No newline at end of file
+        pylint --rcfile=.pylintrc $(git ls-files '*.py')
diff --git a/.pylintrc b/.pylintrc
index 21038f4..bf58994 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -447,7 +447,7 @@ max-bool-expr=5
 max-branches=12
 
 # Maximum number of locals for function / method body.
-max-locals=15
+max-locals=20
 
 # Maximum number of parents for a class (see R0901).
 max-parents=15
diff --git a/django_walletpass/admin.py b/django_walletpass/admin.py
index f9a53e9..fff6cd1 100644
--- a/django_walletpass/admin.py
+++ b/django_walletpass/admin.py
@@ -34,8 +34,7 @@ class LogAdmin(admin.ModelAdmin):
     def pass_(self, obj: Log):
         if obj.pazz_id:
             url = reverse(
-                "admin:%s_%s_change"
-                % (obj.pazz._meta.app_label, obj.pazz._meta.model_name),
+                f"admin:{obj.pazz._meta.app_label}_{obj.pazz._meta.model_name}_change",
                 args=[obj.pazz_id],
             )
             return format_html(
@@ -69,13 +68,16 @@ class PassAdmin(admin.ModelAdmin):
     def wallet_pass_(self, obj: Pass):
         if obj.data:
             return format_html(
-                Template(
-                    "{% load static %}<a href='{url}' alt='{title}'><img src='{% static 'admin/passbook_icon.svg' %}'/></a>"
-                ).render(Context({})),
+                Template('''
+                    {% load static %}
+                    <a href='{url}' alt='{title}'>
+                        <img src='{% static 'admin/passbook_icon.svg' %}'/>
+                    </a>
+                ''').render(Context({})),
                 url=obj.data.url,
                 title=obj.data.name,
             )
-        return
+        return ""
 
     wallet_pass_.short_description = "Pass"
 
@@ -90,8 +92,7 @@ class RegistrationAdmin(admin.ModelAdmin):
     def pass_(self, obj: Registration):
         if obj.pazz_id:
             url = reverse(
-                "admin:%s_%s_change"
-                % (obj.pazz._meta.app_label, obj.pazz._meta.model_name),
+                f"admin:{obj.pazz._meta.app_label}_{obj.pazz._meta.model_name}_change",
                 args=[obj.pazz_id],
             )
             return format_html(
@@ -99,6 +100,6 @@ def pass_(self, obj: Registration):
                 url=url,
                 title=obj.pazz.serial_number,
             )
-        return
+        return ""
 
     pass_.short_description = "Pass"
diff --git a/django_walletpass/models.py b/django_walletpass/models.py
index d35a95f..89f9aab 100644
--- a/django_walletpass/models.py
+++ b/django_walletpass/models.py
@@ -293,7 +293,7 @@ def __unicode__(self):
         return self.serial_number
 
     def __str__(self):
-        return self.serial_number
+        return str(self.serial_number)
 
     class Meta:
         verbose_name_plural = "passes"
@@ -319,7 +319,7 @@ def __unicode__(self):
         return self.device_library_identifier
 
     def __str__(self):
-        return self.device_library_identifier
+        return str(self.device_library_identifier)
 
 
 class Log(models.Model):
@@ -345,10 +345,12 @@ def __str__(self):
 
     @classmethod
     def parse_log(cls, log, message):
+        # pylint: disable=line-too-long
         pattern_register = r"\[(.*?)\]\s(.*?)\s\(for device (.*?), pass type (.*?), serial number (.*?); with web service url (.*?)\)\s(.*?): (.*$)"
         pattern_get = r"\[(.*?)\]\s(.*?)\s\(pass type (.*?), serial number (.*?), if-modified-since \(.*?\); with web service url (.*?)\) (.*?): (.*$)"
         pattern_web_service_error = r"\[(.*?)\]\s(.*?)\sfor (.*?)\s\((.*?)\):\s(.*$)"
         pattern_get_warning = r"\[(.*?)\]\s(.*?)\s\(pass type (.*?), serial number (.*?), if-modified-since \(.*?\); with web service url (.*?)\) (.*?): (.*\.)\s(.*$)"
+        # pylint: disable=line-too-long
 
         match_register = re.match(pattern_register, message)
         match_get = re.match(pattern_get, message)
diff --git a/django_walletpass/urls.py b/django_walletpass/urls.py
index 883bbfa..53028e4 100644
--- a/django_walletpass/urls.py
+++ b/django_walletpass/urls.py
@@ -1,4 +1,4 @@
-from django.urls import re_path, path
+from django.urls import re_path
 from . import classviews
 
 urlpatterns = [