diff --git a/dev/generate_flavours.py b/dev/generate_flavours.py
index aeb36390..34caecef 100644
--- a/dev/generate_flavours.py
+++ b/dev/generate_flavours.py
@@ -118,27 +118,17 @@ def __init_subclass__(cls: Any, **kwargs):
 
 def _fix_abstract_file_system(x: str) -> str:
     x = re.sub(
-        "protocol = 'abstract'",
-        "protocol: str | tuple[str, ...] = 'abstract'",
-        x
-    )
-    x = re.sub(
-        "root_marker = ''",
-        "root_marker: Literal['', '/'] = ''",
-        x
-    )
-    x = re.sub(
-        "sep = '/'",
-        "sep: Literal['/'] = '/'",
-        x
+        "protocol = 'abstract'", "protocol: str | tuple[str, ...] = 'abstract'", x
     )
+    x = re.sub("root_marker = ''", "root_marker: Literal['', '/'] = ''", x)
+    x = re.sub("sep = '/'", "sep: Literal['/'] = '/'", x)
     return x
 
 
 def _fix_azure_blob_file_system(x: str) -> str:
     x = re.sub(
         r"if isinstance\(path, list\):",
-        'if isinstance(path, list):  # type: ignore[unreachable]',
+        "if isinstance(path, list):  # type: ignore[unreachable]",
         x,
     )
     x = re.sub(
diff --git a/noxfile.py b/noxfile.py
index 74ebd6ba..88b1cead 100644
--- a/noxfile.py
+++ b/noxfile.py
@@ -96,10 +96,13 @@ def typesafety(session):
     session.install("-e", ".[tests]")
     session.run(
         "python",
-        "-m", "pytest",
+        "-m",
+        "pytest",
         "-v",
-        "-p", "pytest-mypy-plugins",
-        "--mypy-pyproject-toml-file", "pyproject.toml",
+        "-p",
+        "pytest-mypy-plugins",
+        "--mypy-pyproject-toml-file",
+        "pyproject.toml",
         "typesafety",
     )
 
diff --git a/upath/_flavour.py b/upath/_flavour.py
index cf13f87c..770365cd 100644
--- a/upath/_flavour.py
+++ b/upath/_flavour.py
@@ -278,9 +278,7 @@ def join(self, path: PathOrStr, *paths: PathOrStr) -> str:
             pN = list(map(self.stringify_path, paths))
             drv = ""
         if self.supports_empty_parts:
-            return drv + self.sep.join(
-                [str_remove_suffix(p0, self.sep), *pN]
-            )
+            return drv + self.sep.join([str_remove_suffix(p0, self.sep), *pN])
         else:
             return drv + posixpath.join(p0, *pN)