Fix linting errors

src/registrar/templatetags/url_helpers.py

@@ -1,5 +1,3 @@
-from urllib.parse import urljoin
-
 from django import template
 from django.urls import reverse
 
@@ -30,8 +28,5 @@ def public_site_url(url_path):
     """
     base_url = settings.GETGOV_PUBLIC_SITE_URL
     # join the two halves with a single slash
-    public_url ="/".join([
-        base_url.rstrip("/"),
-        url_path.lstrip("/")
-    ])
+    public_url = "/".join([base_url.rstrip("/"), url_path.lstrip("/")])
     return public_url

src/registrar/tests/test_templatetags.py

@@ -4,8 +4,8 @@ from django.conf import settings
 from django.test import TestCase
 from django.template import Context, Template
 
-class TestTemplateTags(TestCase):
 
+class TestTemplateTags(TestCase):
     def _render_template(self, string, context=None):
         """Helper method to render a template given as a string.