diff --git a/ip_pool/models.py b/ip_pool/models.py
index a8e267d..bc6f771 100644
--- a/ip_pool/models.py
+++ b/ip_pool/models.py
@@ -1,13 +1,10 @@
-from datetime import timedelta
 from ipaddress import ip_network, ip_address
 from typing import Optional, Generator
 
-from django.conf import settings
 from django.db.utils import IntegrityError
 from django.shortcuts import resolve_url
-from django.core.exceptions import ValidationError, ImproperlyConfigured
+from django.core.exceptions import ValidationError
 from django.db import models
-from django.utils.timezone import now
 from django.utils.translation import gettext_lazy as _
 
 from djing.fields import MACAddressField
@@ -21,7 +18,8 @@ class NetworkModel(models.Model):
 
     network = GenericIpAddressWithPrefix(
         verbose_name=_('IP network'),
-        help_text=_('Ip address of network. For example: 192.168.1.0 or fde8:6789:1234:1::'),
+        help_text=_('Ip address of network. For example: '
+                    '192.168.1.0 or fde8:6789:1234:1::'),
         unique=True
     )
     NETWORK_KINDS = (
@@ -31,7 +29,10 @@ class NetworkModel(models.Model):
         ('device', _('Devices')),
         ('admin', _('Admin'))
     )
-    kind = models.CharField(_('Kind of network'), max_length=6, choices=NETWORK_KINDS, default='guest')
+    kind = models.CharField(
+        _('Kind of network'), max_length=6,
+        choices=NETWORK_KINDS, default='guest'
+    )
     description = models.CharField(_('Description'), max_length=64)
     groups = models.ManyToManyField(Group, verbose_name=_('Groups'))
 
@@ -56,33 +57,53 @@ class NetworkModel(models.Model):
     def clean(self):
         errs = {}
         if self.network is None:
-            errs['network'] = ValidationError(_('Network is invalid'), code='invalid')
+            errs['network'] = ValidationError(
+                _('Network is invalid'),
+                code='invalid'
+            )
             raise ValidationError(errs)
         net = self.get_network()
         if self.ip_start is None:
-            errs['ip_start'] = ValidationError(_('Ip start is invalid'), code='invalid')
+            errs['ip_start'] = ValidationError(
+                _('Ip start is invalid'),
+                code='invalid'
+            )
             raise ValidationError(errs)
         start_ip = ip_address(self.ip_start)
         if start_ip not in net:
-            errs['ip_start'] = ValidationError(_('Start ip must be in subnet of specified network'), code='invalid')
+            errs['ip_start'] = ValidationError(
+                _('Start ip must be in subnet of specified network'),
+                code='invalid'
+            )
         if self.ip_end is None:
-            errs['ip_end'] = ValidationError(_('Ip end is invalid'), code='invalid')
+            errs['ip_end'] = ValidationError(
+                _('Ip end is invalid'),
+                code='invalid'
+            )
             raise ValidationError(errs)
         end_ip = ip_address(self.ip_end)
         if end_ip not in net:
-            errs['ip_end'] = ValidationError(_('End ip must be in subnet of specified network'), code='invalid')
+            errs['ip_end'] = ValidationError(
+                _('End ip must be in subnet of specified network'),
+                code='invalid'
+            )
         if errs:
             raise ValidationError(errs)
 
-        other_nets = NetworkModel.objects.exclude(pk=self.pk).only('network').order_by('network')
+        other_nets = NetworkModel.objects.exclude(
+            pk=self.pk
+        ).only('network').order_by('network')
         if not other_nets.exists():
             return
         for onet in other_nets.iterator():
             onet_netw = onet.get_network()
             if net.overlaps(onet_netw):
-                errs['network'] = ValidationError(_('Network is overlaps with %(other_network)s'), params={
-                    'other_network': str(onet_netw)
-                })
+                errs['network'] = ValidationError(
+                    _('Network is overlaps with %(other_network)s'),
+                    params={
+                        'other_network': str(onet_netw)
+                    }
+                )
                 raise ValidationError(errs)
 
     def get_scope(self) -> str:
@@ -108,7 +129,8 @@ class NetworkModel(models.Model):
     def get_free_ip(self, employed_ips: Optional[Generator]):
         """
         Find free ip in network.
-        :param employed_ips: Sorted from less to more ip addresses from current network.
+        :param employed_ips: Sorted from less to more
+         ip addresses from current network.
         :return: single finded ip
         """
         network = self.get_network()
@@ -144,7 +166,10 @@ class IpLeaseManager(models.Manager):
         netw = network.get_network()
         work_range_start_ip = ip_address(network.ip_start)
         work_range_end_ip = ip_address(network.ip_end)
-        employed_ip_queryset = self.filter(network=network, is_dynamic=False).order_by('ip').only('ip')
+        employed_ip_queryset = self.filter(
+            network=network,
+            is_dynamic=False
+        ).order_by('ip').only('ip')
 
         if employed_ip_queryset.exists():
             used_ip_gen = employed_ip_queryset.iterator()
@@ -164,7 +189,8 @@ class IpLeaseManager(models.Manager):
                 if work_range_start_ip <= net <= work_range_end_ip:
                     return net
 
-    def create_from_ip(self, ip: str, net: Optional[NetworkModel], mac=None, is_dynamic=True):
+    def create_from_ip(self, ip: str, net: Optional[NetworkModel],
+                       mac=None, is_dynamic=True):
         # ip = ip_address(ip)
         try:
             return self.create(