diff --git a/uritemplate/api.py b/uritemplate/api.py
index ac75473..8da3914 100644
--- a/uritemplate/api.py
+++ b/uritemplate/api.py
@@ -6,6 +6,7 @@
 This module contains the very simple API provided by uritemplate.
 
 """
+
 import typing as t
 
 from uritemplate import variable
diff --git a/uritemplate/template.py b/uritemplate/template.py
index 73ef89c..3205380 100644
--- a/uritemplate/template.py
+++ b/uritemplate/template.py
@@ -14,6 +14,7 @@
 >
 
 """
+
 import re
 import typing as t
 
@@ -35,7 +36,6 @@ def _merge(
 
 
 class URITemplate:
-
     """This parses the template and will be used to expand it.
 
     This is the most important object as the center of the API.
diff --git a/uritemplate/variable.py b/uritemplate/variable.py
index da406ca..0436f21 100644
--- a/uritemplate/variable.py
+++ b/uritemplate/variable.py
@@ -14,6 +14,7 @@
 >
 
 """
+
 import collections.abc
 import typing as t
 import urllib.parse
@@ -29,7 +30,6 @@
 
 
 class URIVariable:
-
     """This object validates everything inside the URITemplate object.
 
     It validates template expansions and will truncate length as decided by
@@ -59,9 +59,9 @@ def __init__(self, var: str):
         #: List of safe characters when quoting the string
         self.safe: str = ""
         #: List of variables in this variable
-        self.variables: t.List[
-            t.Tuple[str, t.MutableMapping[str, t.Any]]
-        ] = []
+        self.variables: t.List[t.Tuple[str, t.MutableMapping[str, t.Any]]] = (
+            []
+        )
         #: List of variable names
         self.variable_names: t.List[str] = []
         #: List of defaults passed in