Fix linting errors

src/registrar/forms/__init__.py

@@ -1,2 +1,2 @@
 from .application_wizard import *
-from .domain import DomainAddUserForm, DomainNameserverForm, NameserverFormset
+from .domain import DomainAddUserForm, NameserverFormset

src/registrar/forms/domain.py

@@ -3,6 +3,7 @@
 from django import forms
 from django.forms import formset_factory
 
+
 class DomainAddUserForm(forms.Form):
 
     """Form for adding a user to a domain."""
@@ -16,6 +17,7 @@ class DomainNameserverForm(forms.Form):
 
     server = forms.CharField(label="Name server")
 
+
 NameserverFormset = formset_factory(
     DomainNameserverForm,
     extra=1,

src/registrar/templatetags/__init__.py

@@ -7,6 +7,7 @@ from django.template.defaulttags import register
 def get_item(dictionary, key):
     return dictionary.get(key)
 
+
 @register.filter
 def concat(arg1, arg2):
     """concatenate arg1 & arg2"""

src/registrar/views/domain.py

@@ -12,7 +12,7 @@ from django.views.generic.edit import DeleteView, FormMixin
 
 from registrar.models import Domain, DomainInvitation, User, UserDomainRole
 
-from ..forms import DomainAddUserForm, DomainNameserverForm, NameserverFormset
+from ..forms import DomainAddUserForm, NameserverFormset
 from ..utility.email import send_templated_email, EmailSendingError
 from .utility import DomainPermission