diff --git a/picard/util/__init__.py b/picard/util/__init__.py
index a83d8b9d930..5f211c6fba5 100644
--- a/picard/util/__init__.py
+++ b/picard/util/__init__.py
@@ -245,7 +245,7 @@ def system_supports_long_paths():
         system_supports_long_paths._supported = supported
         return supported
     except OSError:
-        log.info('Failed reading LongPathsEnabled from registry')
+        log.info("Failed reading LongPathsEnabled from registry")
         return False
 
 
@@ -257,7 +257,7 @@ def normpath(path):
         # realpath can fail if path does not exist or is not accessible
         # or on Windows if drives are mounted without mount manager
         # (see https://tickets.metabrainz.org/browse/PICARD-2425).
-        log.warning('Failed getting realpath for "%s": %s', path, why)
+        log.warning("Failed getting realpath for `%s`: %s", path, why)
     # If the path is longer than 259 characters on Windows, prepend the \\?\
     # prefix. This enables access to long paths using the Windows API. See
     # https://docs.microsoft.com/en-us/windows/win32/fileio/maximum-file-path-limitation
@@ -400,7 +400,7 @@ def translate_from_sortname(name, sortname):
     """'Translate' the artist name by reversing the sortname."""
     for c in name:
         ctg = unicodedata.category(c)
-        if ctg[0] == "L" and unicodedata.name(c).find("LATIN") == -1:
+        if ctg[0] == "L" and unicodedata.name(c).find('LATIN') == -1:
             for separator in (" & ", "; ", " and ", " vs. ", " with ", " y "):
                 if separator in sortname:
                     parts = sortname.split(separator)
@@ -749,11 +749,11 @@ def build_qurl(host, port=80, path=None, queryargs=None):
     url.setHost(host)
 
     if port == 443 or host in MUSICBRAINZ_SERVERS:
-        url.setScheme("https")
+        url.setScheme('https')
     elif port == 80:
-        url.setScheme("http")
+        url.setScheme('http')
     else:
-        url.setScheme("http")
+        url.setScheme('http')
         url.setPort(port)
 
     if path is not None:
diff --git a/picard/util/bytes2human.py b/picard/util/bytes2human.py
index 5794a5aa8f1..a26a117feef 100644
--- a/picard/util/bytes2human.py
+++ b/picard/util/bytes2human.py
@@ -34,17 +34,17 @@
 
 # used to force gettextization
 _BYTES_STRINGS_I18N = (
-    N_('%(value)s B'),
-    N_('%(value)s kB'),
-    N_('%(value)s KiB'),
-    N_('%(value)s MB'),
-    N_('%(value)s MiB'),
-    N_('%(value)s GB'),
-    N_('%(value)s GiB'),
-    N_('%(value)s TB'),
-    N_('%(value)s TiB'),
-    N_('%(value)s PB'),
-    N_('%(value)s PiB'),
+    N_("%(value)s B"),
+    N_("%(value)s kB"),
+    N_("%(value)s KiB"),
+    N_("%(value)s MB"),
+    N_("%(value)s MiB"),
+    N_("%(value)s GB"),
+    N_("%(value)s GiB"),
+    N_("%(value)s TB"),
+    N_("%(value)s TiB"),
+    N_("%(value)s PB"),
+    N_("%(value)s PiB"),
 )
 
 
@@ -116,9 +116,9 @@ def calc_unit(number, multiple=1000):
     elif multiple == 1024:
         k, b = 'K', 'iB'
     else:
-        raise ValueError('multiple parameter has to be 1000 or 1024')
+        raise ValueError("multiple parameter has to be 1000 or 1024")
 
-    suffixes = ["B"] + [i + b for i in k + "MGTP"]
+    suffixes = ['B'] + [i + b for i in k + 'MGTP']
     for suffix in suffixes:
         if n < multiple or suffix == suffixes[-1]:
             return (sign * n, suffix)
diff --git a/picard/util/cdrom.py b/picard/util/cdrom.py
index 8d8c31d0f2d..d43b11046c3 100644
--- a/picard/util/cdrom.py
+++ b/picard/util/cdrom.py
@@ -63,7 +63,7 @@ def _generic_iter_drives():
     config = get_config()
     yield from (
         device.strip() for device
-        in config.setting["cd_lookup_device"].split(",")
+        in config.setting['cd_lookup_device'].split(',')
         if device and not device.isspace()
     )
 
@@ -97,7 +97,7 @@ def _iter_drives():
         mask = GetLogicalDrives()
         for i in range(26):
             if mask >> i & 1:
-                drive = chr(i + ord("A")) + ":"
+                drive = chr(i + ord('A')) + ':'
                 if GetDriveType(drive) == DRIVE_TYPE_CDROM:
                     yield drive
 
diff --git a/picard/util/checkupdate.py b/picard/util/checkupdate.py
index f2ac320cff4..78593e1fa0d 100644
--- a/picard/util/checkupdate.py
+++ b/picard/util/checkupdate.py
@@ -128,7 +128,7 @@ def _display_results(self):
             try:
                 test_version = Version(*version_tuple)
             except (TypeError, VersionError):
-                log.error('Invalid version %r for update level %s.', version_tuple, update_level)
+                log.error("Invalid version %r for update level %s.", version_tuple, update_level)
                 continue
             if self._update_level >= test_key and test_version > high_version:
                 key = PROGRAM_UPDATE_LEVELS[test_key]['name']
@@ -153,7 +153,7 @@ def _display_results(self):
                 if self._update_level in PROGRAM_UPDATE_LEVELS:
                     update_level = PROGRAM_UPDATE_LEVELS[self._update_level]['title']
                 else:
-                    update_level = N_('unknown')
+                    update_level = N_("unknown")
                 QMessageBox.information(
                     self._parent,
                     _("Picard Update"),
diff --git a/picard/util/emptydir.py b/picard/util/emptydir.py
index 48e1aa37bf6..5edb4d86c84 100644
--- a/picard/util/emptydir.py
+++ b/picard/util/emptydir.py
@@ -84,8 +84,8 @@ def rm_empty_dir(path):
                        or considered a special directory.
     """
     if os.path.realpath(path) in PROTECTED_DIRECTORIES:
-        raise SkipRemoveDir('%s is a protected directory' % path)
+        raise SkipRemoveDir("%s is a protected directory" % path)
     elif not is_empty_dir(path):
-        raise SkipRemoveDir('%s is not empty' % path)
+        raise SkipRemoveDir("%s is not empty" % path)
     else:
         shutil.rmtree(path)