diff --git a/django_afip/models.py b/django_afip/models.py
index 20f0ad1..25fb5b0 100644
--- a/django_afip/models.py
+++ b/django_afip/models.py
@@ -17,8 +17,6 @@
 from typing import ClassVar
 from typing import Generic
 from typing import TypeVar
-from typing import Dict
-from typing import Optional as TypeOptional
 from uuid import uuid4
 
 from django import VERSION as DJANGO_VERSION
@@ -33,7 +31,6 @@
 from django.db.models import F
 from django.db.models import Q
 from django.db.models import Sum
-from django.db.models.fields.files import FieldFile
 from django.utils.module_loading import import_string
 from django.utils.translation import gettext_lazy as _
 from lxml import etree
@@ -54,6 +51,7 @@
 
 if TYPE_CHECKING:
     from django.core.files.storage import Storage
+    from django.db.models.fields.files import FieldFile
 
 logger = logging.getLogger(__name__)
 
@@ -129,11 +127,11 @@ def first_currency() -> int | None:
 def _get_storage_from_settings(setting_name: str) -> Storage:
     path = getattr(settings, setting_name, None)
     if not path:
-        if DJANGO_VERSION >= (4,2):
+        if DJANGO_VERSION >= (4, 2):
             from django.core.files.storage import default_storage
+
             return default_storage
-        else:
-            return import_string(settings.DEFAULT_FILE_STORAGE)()
+        return import_string(settings.DEFAULT_FILE_STORAGE)()
     return import_string(path)
 
 
@@ -428,7 +426,7 @@ class TaxPayer(models.Model):
         help_text=_("A logo to use when generating printable receipts."),
     )
 
-    _old_files: Dict[str, TypeOptional[FieldFile]] = {}
+    _old_files: dict[str, FieldFile | None]
 
     @property
     def logo_as_data_uri(self) -> str:
@@ -574,21 +572,20 @@ def fetch_points_of_sales(
         results = []
 
         existing_pos_dict = {
-            pos.number: pos
-            for pos in PointOfSales.objects.filter(owner=self)
+            pos.number: pos for pos in PointOfSales.objects.filter(owner=self)
         }
-        
+
         for pos_data in response.ResultGet.PtoVenta:
             pos_number = pos_data.Nro
             issuance_type = pos_data.EmisionTipo
             is_blocked = pos_data.Bloqueado == "S"
-            drop_date = parsers.parse_date_maybe(pos_data.FchBaja) 
-            
+            drop_date = parsers.parse_date_maybe(pos_data.FchBaja)
+
             if pos_number in existing_pos_dict:
                 pos = existing_pos_dict[pos_number]
 
                 is_modified = False
-                
+
                 if pos.issuance_type != issuance_type:
                     pos.issuance_type = issuance_type
                     is_modified = True
@@ -1381,8 +1378,8 @@ def approximate_date(self: Receipt) -> bool:
         If a receipt should have been validated in a past date, adjust its date as close
         as possible:
 
-            - Receipts can only be validated with dates as far as 14 days ago for 
-              services and 5 days ago for products. If the receipt date is older 
+            - Receipts can only be validated with dates as far as 14 days ago for
+              services and 5 days ago for products. If the receipt date is older
               than that, set it to 14 or 5 days ago.
             - If other receipts have been validated on a more recent date, the receipt
               cannot be older than the most recent one.
diff --git a/django_afip/signals.py b/django_afip/signals.py
index ac725ce..7e5628a 100644
--- a/django_afip/signals.py
+++ b/django_afip/signals.py
@@ -2,7 +2,8 @@
 
 from typing import TYPE_CHECKING
 
-from django.db.models.signals import pre_save, post_save
+from django.db.models.signals import post_save
+from django.db.models.signals import pre_save
 from django.dispatch import receiver
 
 from django_afip import models
@@ -21,7 +22,8 @@ def update_certificate_expiration(
         instance.certificate_expiration = instance.get_certificate_expiration()
 
 
-FILE_FIELDS = ['certificate', 'logo']
+FILE_FIELDS = ["certificate", "logo"]
+
 
 # Store old files before saving.
 @receiver(pre_save, sender=models.TaxPayer)
@@ -34,10 +36,13 @@ def store_old_files(
         try:
             old_instance = sender.objects.get(pk=instance.pk)
             # Save the reference of the old files in the model.
-            instance._old_files = {field: getattr(old_instance, field) for field in FILE_FIELDS}
+            instance._old_files = {
+                field: getattr(old_instance, field) for field in FILE_FIELDS
+            }
         except sender.DoesNotExist:
             instance._old_files = {}
 
+
 # Delete old files after saving.
 @receiver(post_save, sender=models.TaxPayer)
 def delete_file_taxpayer(
@@ -46,9 +51,9 @@ def delete_file_taxpayer(
     **kwargs,
 ) -> None:
     if not instance.pk:
-        return # The instance is new, there are no old files to delete.
-    
-    old_files = getattr(instance, '_old_files', {})
+        return  # The instance is new, there are no old files to delete.
+
+    old_files = getattr(instance, "_old_files", {})
 
     for field_name in FILE_FIELDS:
         old_file = old_files.get(field_name)
@@ -56,4 +61,4 @@ def delete_file_taxpayer(
 
         if old_file and old_file != new_file:
             # Delete the old file from storage.
-            old_file.delete(save=False)
\ No newline at end of file
+            old_file.delete(save=False)