Configures ruff as the one stop linter and resolves warnings it raised

src/documents/migrations/0014_document_checksum.py

@@ -1,6 +1,4 @@
-# -*- coding: utf-8 -*-
 # Generated by Django 1.9.4 on 2016-03-28 19:09
-from __future__ import unicode_literals
 
 import gnupg
 import hashlib
@@ -13,7 +11,7 @@ from django.template.defaultfilters import slugify
 from django.utils.termcolors import colorize as colourise  # Spelling hurts me
 
 
-class GnuPG(object):
+class GnuPG:
     """
     A handy singleton to use when handling encrypted files.
     """
@@ -27,11 +25,14 @@ class GnuPG(object):
     @classmethod
     def encrypted(cls, file_handle):
         return cls.gpg.encrypt_file(
-            file_handle, recipients=None, passphrase=settings.PASSPHRASE, symmetric=True
+            file_handle,
+            recipients=None,
+            passphrase=settings.PASSPHRASE,
+            symmetric=True,
         ).data
 
 
-class Document(object):
+class Document:
     """
     Django's migrations restrict access to model methods, so this is a snapshot
     of the methods that existed at the time this migration was written, since
@@ -49,9 +50,9 @@ class Document(object):
     def __str__(self):
         created = self.created.strftime("%Y%m%d%H%M%S")
         if self.correspondent and self.title:
-            return "{}: {} - {}".format(created, self.correspondent, self.title)
+            return f"{created}: {self.correspondent} - {self.title}"
         if self.correspondent or self.title:
-            return "{}: {}".format(created, self.correspondent or self.title)
+            return f"{created}: {self.correspondent or self.title}"
         return str(created)
 
     @property
@@ -60,7 +61,7 @@ class Document(object):
             settings.MEDIA_ROOT,
             "documents",
             "originals",
-            "{:07}.{}.gpg".format(self.pk, self.file_type),
+            f"{self.pk:07}.{self.file_type}.gpg",
         )
 
     @property
@@ -88,7 +89,7 @@ def set_checksums(apps, schema_editor):
             "  order."
             "\n",
             opts=("bold",),
-        )
+        ),
     )
 
     sums = {}
@@ -101,7 +102,7 @@ def set_checksums(apps, schema_editor):
                 colourise("*", fg="green"),
                 colourise("Generating a checksum for", fg="white"),
                 colourise(document.file_name, fg="cyan"),
-            )
+            ),
         )
 
         with document.source_file as encrypted:
@@ -122,15 +123,16 @@ def set_checksums(apps, schema_editor):
                     fg="yellow",
                 ),
                 doc1=colourise(
-                    "  * {} (id: {})".format(sums[checksum][1], sums[checksum][0]),
+                    f"  * {sums[checksum][1]} (id: {sums[checksum][0]})",
                     fg="red",
                 ),
                 doc2=colourise(
-                    "  * {} (id: {})".format(document.file_name, document.pk), fg="red"
+                    f"  * {document.file_name} (id: {document.pk})",
+                    fg="red",
                 ),
                 code=colourise(
                     "  $ echo 'DELETE FROM documents_document WHERE id = {pk};' | ./manage.py dbshell".format(
-                        pk=document.pk
+                        pk=document.pk,
                     ),
                     fg="green",
                 ),
@@ -171,7 +173,8 @@ class Migration(migrations.Migration):
             model_name="document",
             name="created",
             field=models.DateTimeField(
-                db_index=True, default=django.utils.timezone.now
+                db_index=True,
+                default=django.utils.timezone.now,
             ),
         ),
         migrations.AlterField(